Preheat oven to 350℉.
Spray an oven safe casserole dish with non-stick spray. Set aside.
Brown ground beef in a large skillet over medium heat, breaking it up into small crumbles with a wooden spoon as it cooks.
Add diced onion and continue to cook until onions soften.
Add diced red bell pepper and continue to cook for a few more minutes till they soften.
Drain off excess grease.
Add taco seasoning and water to the pan.
Simmer until the liquid in the pan evaporates and beef mixture thickens.
Stir in drained Rotel and sour cream. Stir to combine everything together.
Place ⅓ of the crushed chips in the bottom of the prepared casserole dish in an even layer.
Spoon ½ the beef mixture over the chips in the casserole dish in an even layer.
Top with a 1½ cups of shredded cheese.
Top with another ⅓ of the chips.
Top with the remaining ½ of the beef mixture.
Finish with the remaining ⅓ of the crushed chips and a final layer of shredded cheese.
Bake in the preheated oven for 20-25 minutes or until cheese is melted and hot and bubbly.
Top each serving with shredded lettuce, chopped tomatoes and a dollop of sour cream.