I hate to use this as a source for anything, even Hitler's views. However, Mein Kampf does use Latin Americans as an example of "European stock" degraded by intermarriage with aboriginals.

To get away from that distasteful topic, Mexico has a rather interesting foreign policy during the interwar and post war periods. For one narrative, I recommend Mexico Between Hitler and Roosevelt, which claims Mexico navigated a rift between the US and Germany. Although I would argue this is far more true of the southern horn countries, it's an interesting idea. In any case, after WWI, US-Mexican relations were incredibly strained due to us intervention in the Mexican revolution. This relationship had improved dramatically by around 1935, but not sufficiently to pull Mexico fully into the US sphere. From around 1938 to 1940, Germany was one of Mexico's largest trading partners, exchanging oil and ammonia (among other goods). Towards the end of this period, Mexico pulled away from Germany. By 1941, Mexico's neutrality towards Germany was largely home and Mexico was an instrumental partner in the 1941 Rio treaty. In 1942 they finally declared war on the axis and eventually sent troops. Less formally, many mexicans supported the us war effort and immigrated to work in the labor limited factories.