So I don't know if there's supposed to be something in the opening post of that, because all I see is blank. The rest of the thread has basically nothing to do with the question, because all it says is how badly Christians were treated after Nobunaga, and other Japanese Christian things, not how well Nobunaga treated Christians.

Now Nobunaga without a doubt treated Christians fairly well and took a liking to a few Jesuits. Certainly it was regarded as widespread knowledge that Nobunaga liked western stuff since, according to Jesuit Luis Frois' History of Japan, everyone were eager to send Nobunaga western stuff and he has chests full of them. Nobunaga also hosted debate between the Jesuits and Buddhist monks, during which he sided with the Jesuits because the monks physically lashed out. Nobunaga seemed to have admired the Jesuits for their tenacity of travelling all the way to Japan and spreading their religion under all sorts of hardship, and also for living simple lives and focusing on their religion instead of corrupt Buddhist monks who lived lavishly, broke their religious teachings, and interfered in politics. Nobunaga himself often conversed with the missionaries and Japanese Christians, telling them to visit him often.

Gaspar Coelho's report to the Jesuit Society dated February 25, 1582 also contain an interesting episode. He reported that Nobunaga once got angry at the Jesuits when he caught a Christian samurai divorce his wife to take another, which was against Christian teachings. This means Nobunaga both knew enough Christian teachings to know it was against Christianity to divorce, and that he thought a Japanese Christian should follow Christian teachings despite it conflicting with Japanese traditions. By the way, after some inspections Nobunaga was apparently satisfied that the missionaries already did their best, also said samurai later had his titles and holdings confiscated for beating his wife and trying to take another woman despite Nobunaga ordering him to get back together with his wife.

The clearest example of Nobunaga's support happened in 1581 during the construction of Azuchi Castle. Azuchi was a hirayama-jiro ("Plains-Mountain Castle", see here on the development of Japanese castles), and it was planned that Oda vassals would live in the mountain sides between Nobunaga on the top and the castle town at the foot of the mountain. The Jesuits wanted to build a seminário (religious school) in Azuchi. They realized the most important converts would be the lords so they needed to be in the mountain sides instead of in the castle town, but the mountain side was too restricted in space for a school. Nobunaga ended up filling in a cove of a lake at the foot of the mountain between the castle and town, and then despite many important vassals asking for the piece of land he gave it to the Jesuits. The Christians were overjoyed that they mobilized donations and manpower from across the area, including from the Christian daimyō like Takayama Ukon, and a 3-stories seminário was construct quickly. Nobunaga was so impressed by this that he himself donated more money to its construction, ordered a couple of neighbouring samurai (according to the Chronicles of Lord Nobunaga one of whom was Nobunaga's nephew) to move and had their houses torn down to give the Jesuits even more room, and gave the Jesuits permission to use the same roof-tiles as the castle, though the Jesuits decided not to line it with gold like the castle, meaning it would be, according to the report, blue tiles that were the most durable in the world.

Given all this, it's perhaps not a surprise that the Jesuits reported that Nobunaga's vassals and son also took an interest in Christianity, and asked to hear from the Jesuits, allowed them to proselytize, and even build churches. So it's fairly likely that, at least in the short term, had Nobunaga not died Christianity would have flourished even more. In fact, the idea that Nobunaga was God's agent sent to destroy Buddhism to allow for a Christian utopia is straight from the Jesuits themselves. Both Frois and Coeho stated that this was the case. So on how well did Oda Nobunaga treat Christians, well he treated them very well indeed.

But does this mean Japan would have turned into a Christian utopia? We of course will never know what didn't happen, but I think it is important to point out here that Nobunaga was never directly threatened by Christianity. All he saw were a bunch of tenacious, religious priests that didn't step out of line like Buddhist monks. What would have been his response when on conquering Kyūshū people cried to him that their families were bought by Portuguese merchants and sold as slaves, or when the inevitable clash happen about whether Christians were to listen to him or to the Pope, or when the English and Dutch show up and tell him proselytizing Jesuits were a first wave and sixth column to conquer Japan by the Hispanics?

Here I want to draw attention to something that happened in 1578. Araki Murashige rebelled against Nobunaga. Takayama Tomoteru and his son Ukon controlled Murashige's Takatsuki Castle, the front line between Murashige and Nobunaga. The first rule of Sengoku warfare is try to bring your enemy's vassals onto your side, and Nobunaga knew both father and son were devote Christians (Christian name Dario and Justo respectively) and so called on Jesuit Gnecchi-Soldo Organtino to go persuade father and son to come back into Nobunaga's fold. However, while Ukon wanted to, Tomoteru felt he owed his rise to Murashige, and Murashige had his daughter and grandson as hostage, and so would not switch sides. Even after Nobunaga offered them gold, land, to switch Murashige's hostages to Nobunaga for their hostages to Murashige, and to protect their honor by putting out public notices that this entire situation is Murashige's fault and even if the hostages are lost the Takayama's are not to blame, even after all that they would not switch sides. A desperate Nobunaga ordered all the Christians rounded up, had a bunch of them brought to him at the front lines, and told Organtino to tell the Takayamas that if they submit they'll be allowed to proselytize all they want, but if they didn't he will kill all the Christians. And according to Frois, Organtino, the Takayamas, and all the Christians believed it.

Of course, we can not ever know for sure. But Nobunaga was willing to go this far for one minor castle and two minor Christian lords for something unrelated to religion, so it certainly cast doubt on the idea that he would've been just as receptive to Christianity once he had to face the issues that the Toyotomi and Tokugawa governments did.

As a post script, Nobunaga's threat shocked the Takayamas into abandoning the castle, with Ukon going to Nobunaga and Tomoteru going to Murashige. Without its lords the castle surrendered to Nobunaga. The Takayamas, the hostages, and the Christians all survived the ordeal.