Preheat the oven to 400 degrees F (200 degrees C).

Whisk together eggs, milk, salsa, bell pepper, onion, and cheese in a bowl. Season with salt and pepper. Set aside.

Heat a large skillet over medium-high heat and stir in ground beef. Cook and stir until beef is crumbly, evenly browned, and no longer pink, 8 to 10 minutes. Drain and discard any excess grease. Stir in taco seasoning.

Spread meat mixture into pie crust placed in a 9-inch pie dish. Pour egg mixture over beef.

Bake in the preheated oven until a knife inserted into the center of the quiche comes out clean, 45 minutes to 1 hour. Cool for 10 minutes before serving warm.