Your question presupposes that the Japanese strategy was to defeat the United States in a head to head military campaign. It wasn't. It was fairly well understood that Japan lacked the industrial capacity to compete militarily with the United States, that's why they attempted to destroy the US Pacific Fleet in a surprise attack on Pearl Harbor. While the destruction of the US battleship fleet was desirable, of more importance was the destruction of the US' three fleet carriers that were deployed to the Pacific,* USS Enterprise*, Lexington and Saratoga. HAd the Japanese been able to achieve that, the US would not have had the naval air capacity to combat Japanese advances in South East Asia and the South Pacific until US industry reached the capacity to replace its carrier losses. By that timer, Japanese hoped to be in a much better strategic situation that they hoped the US would perhaps seek a peace agreement rather then continue fighting.
Source: The Second World War by Antony Beevor
Because of the Japanese historical experience, which was that a single decisive victory could bring a country to the negotiating table, and because of factional battles that were resolved by the United States.
"Defeat" at Nomonhan/Khalkhin Gol had little to do with Japan abandoning its war plans, as Nomonhan was only a defeat in the technical sense. Despite being heavily outnumbered and outgunned, the Japanese lost considerably fewer troops than the Soviets. The Soviets themselves were not pleased with the result of the battle. General Grigori Shtern, who commanded in conjunction with Zhukov on the Soviet side, later stated:
Japan had two understrength divisions against eight Soviet divisions. We were also superior in tanks and artillery, but we lost more than the enemy. The number of casualties were huge, and medical beds were in short supply. The victory was so costly that we didn't advertise it to the world, and the incident was a prelude to impending military disaster. After the ceasefire, I investigated the battle and examined issues such as erroneous operations and delays in military preparations
Because of this, the Japanese plan to invade the Soviet Union did not stop with the Battle of Nomonhan. In June 1941, the German invasion of the Soviet Union had left the Soviet Union exposed. Despite concluding a non-aggression pact 2 months earlier, the Japanese government authorized preparation for the "Kantogun Special Maneuvers", an invasion of the Soviet Union intending to cut the Trans-Siberian railway in two places. This was lobbied for by Foreign Minister Matsuoka Yosuke, Chief of Staff Sugiyama Hajime, and Privy Council Chairman Hara Yoshimichi, who succeeded in persuading the Emperor over the objections of the Navy (who wanted to attack the United States), and Prime Minister Konoe Fumimaro (who wanted to win a decisive victory in his "pet war" in China). The plan specified that the invasion was to begin on the 10th of September, 1941 at the latest.
However, on August 1, less than a month after the Emperor gave his go-ahead, the United States announced a total oil embargo on Japan in retaliation for the Japanese occupation of French Indochina. On the 7th, the government decided that the impending oil shortage would make war against the Soviet Union impossible, and that the seizure of the oilfields of Southeast Asia was key to securing Japanese fuel reserves. Despite this, the zealots of the Kantogun continued plotting an invasion of the Soviet Union until 1943.
The one hundred eighty degree shift in Japan's war plans led to an even more daunting challenge, but one which was more familiar to the country. Japan had to defeat an on-paper superior naval force and force it to the table. "Fortunately", the naval command had the precedent of the Russo-Japanese War, in which a theoretically superior Russian fleet was ruined by superior gunnery and innovative tactics.
Two strategies were extensively simulated in the navy's wargames. One favored engaging the United States Navy as it attempted to reinforce the Philippines, while the second, a surprise attack on Pearl Harbor, became fashionable following the Royal Navy's success in destroying the Italian fleet at Taranto.
The chosen operation - the raid on Pearl Harbor - was a resounding success in conventional terms, as were the followup operations. In February 1942, a combined Allied fleet was destroyed off the coast of Surabaya in the Java Sea. More surprisingly, the Imperial Army, trained to fight the Soviets in Manchuria and Siberia, actually performed quite well in the Malayan and Philippine jungles and pulled off surprising victories. The navy followed up on the Fall of Singapore by entering the Indian Ocean, and mauling the Royal Navy in Operation C. A month later, the Navy won a tactical victory at the Battle of the Coral Sea.
According to the Navy's historical experience, the Allies should have sued for peace as the Tsar did following the loss of his Battleship row at Tsushima. They did not. Undeterred, the IJN continued its quest for a Tsushima-style "decisive victory". A major setback at Midway was partially corrected by the Battle of Savo Island. For two more years, the IJN hoarded its battleships in a vain attempt to find an opening to destroy the American fleet. This finally ended in the decisive Battle of Leyte Gulf, where a Japanese fleet - almost without trained pilots at this point - was crushed by an overwhelmingly superior American fleet, most of which had been launched or re-launched following extensive repairs in the prior 2 years.
Why did the Navy not anticipate this disaster? Because in historical terms, it was "impossible". Conventional wisdom at the time asserted that navies took a long time to build. The United States, through its huge industrial base and brilliant engineering, turned this on its head. By late 1942, the United States did not have a single operable carrier or battleship left in the Pacific. At Leyte Gulf less than two years later, it had 34 carriers and 12 battleships. The IJN had triumphed over two naval forces that were superior on paper before - the Qing navy in 1895, and the Russian navy in 1905. Both times, a decisive victory granted Japan uncontested control of the sea.
Yamamoto Isoroku, after the attack on Pearl Harbor, lamented, "we have awoken a sleeping giant". In feeling this way, he was almost completely alone. Military and political leaders in Japan, as well as in its European allies, were surprised but exhilerated at the successes of 1941-42. In May 1942, Tojo declared a list of Japan's "non-negotiable demands", including Washington State, Alaska, Hawaii, Ecuador, Panama, Colombia, Honduras, Cuba, Panama, El Salvador, Nicaragua, Guatemala, Burma, India, Australia, Jamaica, New Zealand, Haiti, Macau, East Timor, Cambodia, Vietnam, Laos, Malaysia, Thailand, and all of China.
There was one man in power who doubted victory in the war and did what he could to stop it, and that was Lord Konoe Fumimaro, Prime Minister between 1937 and 1941. Konoe was a nationalist himself - as early as 1919, he condemned the Treaty of Versailles as "Anglo-American dominated". In the 1920s and 30s, he claimed that understanding with the West was pointless because they would "always" be racist against Japan anyway. Shortly after becoming Prime Minister, he initiated a "Holy War" against China which made the Japanese army notorious for atrocities. Despite this, he, unlike most of the military, feared both American and Soviet industry. He was the main, if not the sole driving force in the widely hated Soviet-Japanese Non-Aggression Pact - so despised that the Emperor did not think twice about ordering an invasion of the USSR just two months later. Tragically, Konoe's policy of negotiation was sabotaged by his own Foreign Minister, Matsuoka Yosuke. As early as April 1941, Roosevelt had gone around his relatively hardline state department and offered to consent to the Japanese takeover of China and even lift restrictions on Japanese immigration to the United States (a pet cause of Japanese politicians across the spectrum at the time), "advised" by a circle of priests. The hawkish Matsuoka intercepted this offer before it got to Konoe, and responded with an absurd counteroffer on Konoe's behalf. By October, Konoe had been replaced by Tojo for the "failure" of his rapproachement policy.
The mentality of the Army and Navy towards war is embodied by one of Tojo and Konoe's last conversations. When Konoe protested that the military's war plans would have unforeseen consequences, Tojo responded:
Occasionally one must gather up enough courage, close his eyes and take the plunge.