I've been to Mexico City. It's absolutely huge. There are probably neighbourhoods where "nomads" are pricing out the locals, but the vast majority of the city isn't affected. What's driving up rents in Mexico City is that it's Mexico City. Most of the people moving there are Mexican.

As for other tourist destinations, yes in tourist destinations there are tourists! Wow. But, there's a lot of places in Mexico that aren't tourist destinations, or are destinations only for Mexican tourists. There are entire cities with millions of inhabitants where you're very unlikely to ever see an American / nomad.