There's a lot of mediocre Mexican food in NYC, including mediocre Mexican food that's dressed up in fancy looking restaurants (like the Rosa Mexicano mini chain, which is fun but really nothing special food-wise).
At the high end Cosme has been on my list of places to try for quite a while. Every time I manage to get a reservation something comes up and we have to cancel. They have a more casual sister restaurant Atla, which I did try a few years ago and thought was good, but wasn't blown away. I think Casa Enrique is the only NYC Mexican restaurant to earn a Michelin star (although it looks like they lost their star last year). I guess I should probably put that on my list, too!
At the low end there are good taco places in almost every neighborhood, but there are also lots of mediocre and even bad taco places, so choose carefully. Here on the Lower East Side my family's preferred place is Essex Taqueria, which makes very good chicken tacos that aren't expensive and are delivered to our home quickly. Avoid Taco Recipes in our neighborhood. You might find more interesting options in Jackson Heights, Queens, where there are more Mexican immigrants. There's a Birria taco truck out there that's particularly well regarded (one of the main reasons my brother in law was sad to move away from Jackson Heights).