Interesting, isn´t it? Chiles (or hot peppers) probably originated in the triangle between Perú, Bolivia and Brazil. At least, the oldest traces (12,000 years) were found there - not in Mexico. Propagation came mainly from birds, but later, humans. Indian food, curiously enough, did not use chiles until the 16th century.I think geography and prevalence of pepper plants/products plays a major role in regional cuisine.
Now, the hottest dishes in the world come from Mexico,Perú - but notably India and south east Asia. The hottest thing I´ve ever eaten was a Sri Lankan aubergine curry and a Thai green curry. So, so hot, I couldn´t finish them. I think even my toenails were perspiring.
We can credit the Spanish, but perhaps more, the Portuguese, for spreading fire around the world!