Preheat the oven to 350 degrees F (175 degrees C).

Heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and discard grease. Stir 3/4 cup water and taco seasoning into ground beef; simmer until water has evaporated, about 5 minutes.

Heat vegetable oil in a separate skillet over medium heat; cook and stir rice in hot oil until fragrant and golden brown, about 5 minutes. Add 1 cup water, salsa, onion, and garlic; bring to a boil. Lower heat, cover the skillet, and simmer until rice is tender and liquid is absorbed, about 15 minutes. Stir ground beef mixture into rice mixture until well combined.

Spoon a layer of ground beef-rice mixture into each bell pepper; top with a layer of Mexican cheese and a layer of nacho cheese-flavored tortilla chips. Repeat layering ingredients into bell peppers, ending with a Mexican cheese layer. Arrange stuffed peppers in a 9x9-inch baking dish.