Vietnamese, Mexican, Thai but not exclusively those. Staying on S Las Vegas Blvd, south of the airport. Will have a car. Thank you.
Lotus of Siam, Red Rock Casino (Anthony Bourdain was totally right about this place -- order from the Northern Thai page of the menu)
Tacos el Gordo, 1500(ish) E Charleston Blvd. (two locations -- Tijuana and LV. No difference between the two. It's like eating in Mexico. Never go here on a Sunday -- line out the door with post-mass locals)
Orchid Vietnamese -- Bahn Mi
Lee's Sandwiches -- Bahn Mi (I prefer this one, but the line is sometimes out the door. If I'm in a hurry, I'll head one block over to Orchid.)
Pho Thanh Hung
And you didn't mention Chinese but here are two good ones (there were three, the most interesting one didn't last):
The lunch counter at Market 168 supermarket -- dim sum (I've eaten here more than any other place in Las Vegas -- great dumplings at giveaway prices. Take a ticket from the counter or you'll never be able to order)
Asian BBQ & Noodle -- rated one of the best Chinese places in the US, by Chinese expats