Sprinkle both sides of the chicken breasts with the taco seasoning and chili powder. Rub in the seasonings as much as you can. Heat the olive oil in a heavy skillet over medium heat. Cook the chicken breasts on both sides until deep golden and totally done in the middle, about 4 minutes per side. Remove from the skillet and let rest for a few minutes. In the same skillet, whisk in the tomato sauce, hot water, and several dashes of hot sauce and bring to a gentle boil. Reduce the heat to low and keep warm. Taste and adjust seasonings (you may need to add a little salt, depending on the taco seasoning you use). Shred the chicken using two forks, then transfer the shredded chicken to the sauce. Toss to coat it in the sauce. If the sauce is too thick, add a little more hot water and allow to simmer for a few minutes. To build the nachos, layer the chips, cheese, and shredded chicken on a dish in several layers, ending with a small layer on top. Microwave the dish (or place it in a 350 degree oven if ovenproof) until the cheese is totally melted. Serve as is or add whatever extras you'd like! Dive into it immediately.