Cook Filling Base: In a large skillet over medium-high heat, crumble and cook the sausage. When halfway done, add onion and jalapeño and cook until sausage is browned. With a slotted spoon, transfer 1 cup of the mixture to a large bowl. Leave the rest in the skillet for the gravy.
Scramble Eggs: In a separate pan, melt butter over medium-low heat. Whisk eggs with a pinch of salt and scramble until soft and slightly undercooked.
Combine Filling: To the bowl with the reserved sausage, add the scrambled eggs, cooked tater tots, and 1/2 cup each of Pepper Jack and Cheddar cheese. Mix gently.
Make Gravy: Return the skillet with remaining sausage to medium heat. Sprinkle flour over the sausage and stir for 1 minute. Slowly whisk in the milk until smooth. Simmer, stirring constantly, until thickened. Season with salt and pepper.
Prep Tortillas: Heat a thin layer of oil in a skillet over medium-high heat. Fry each tortilla for 10-15 seconds per side until pliable and slightly puffed.
Assemble: Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish. Fill each tortilla with the egg mixture, roll tightly, and place seam-side down in the dish.
Bake: Pour the sausage gravy evenly over the enchiladas. Top with the remaining 1 cup of cheese. Bake uncovered for 30-40 minutes, until bubbly and golden. Let rest for 5-10 minutes before serving.
