Brown the hamburger in a skillet and drain excess fat.

Add chopped onion to the skillet and cook until softened.

Stir in taco seasoning and water, then simmer until thickened.

In a separate saucepan, combine tomato paste, water, and enchilada mix.

Bring the enchilada sauce to a boil, then reduce heat and simmer.

Dip each flour shell into the enchilada sauce to soften.

Place the dipped shell in a greased baking dish.

Fill the center of the shell with the hamburger mixture, onion, and green chilies.

Roll up the enchilada and place it seam-side down in the baking dish.

Pour remaining enchilada sauce over the rolled enchiladas.

Cover the enchiladas with Monterey Jack and Cheddar cheese.

Bake in a preheated oven at 350°F (175°C) for 30-45 minutes, or until golden brown and bubbly.