Preheat the oven to 325 degrees F (165 degrees C). Stir tortilla chips and butter together in a bowl. Press into the bottom of a 9-inch springform pan. Bake in the preheated oven for 10 minutes. Remove crust from oven, leaving oven on. Cool on a wire rack. Heat a large skillet over medium heat. Add beef and cook, stirring, until crumbly and no longer pink, 7 to 10 minutes. Drain and discard grease. Pat beef dry with paper towels and return to the skillet. Reserve 1 teaspoon taco seasoning mix. Stir remaining taco seasoning and salsa into beef. Cook over medium heat, stirring occasionally, until liquid evaporates, about 5 minutes. Beat cream cheese in a bowl using an electric mixer until fluffy. Add eggs and reserved taco seasoning mix, beating until blended. Add Cheddar cheese and beat until blended. Spread mixture evenly over crust and 1 inch up sides of pan. Spoon in beef mixture. Combine sour cream and flour in a bowl; spread over cheesecake. Bake in the hot oven for 25 minutes. Cool in the pan on a wire rack for 10 minutes. Run a knife around the edges and release sides of pan. Serve warm, cold, or room temperature with a topping of lettuce, tomato, and avocado.