Thai food in vegas can be quite difficult to find. Next to Lotus of Siam, Nittaya's is my favorite. They have some interesting dishes such as the spinach salad and the charred peppers and are also willing to account for those of us with dietary restrictions. In addition to the above mentioned dishes I also had the basil eggplant with tofu. I wish I had ordered it a 5 spicy, as I got the 3 and tasted no spice at all. The flavor was great, and would get it again, just order a higher spice level.
The decor is great, the waitstaff is nice. The place is tiny so reservations are recommended it was packed when we went.