¾ cup green taco sauce or salsa verde (not chunky)
½ cup light sour cream
Shredded Monterey Jack cheese, to taste
½ cup finely chopped cilantro
Place a rack in the bottom third of the oven and preheat to 350. With nonstick cooking spray, lightly coat a 13 x 9 inches pan and a piece of foil large enough to cover the pan.
In medium-high, heat the oil in a large skillet. Add the onion and cook, stirring frequently, until clear (about 4 minutes). Add chicken, chilis, and chili powder, and cook for 2 minutes, continuing to stir. Remove from heat and stir in the corn, spinach, sour cream, cheese and salt.
Placed between damp paper towels, microwave tortillas until hot and soft (about 1 minutes). Cover to keep warm. Removing 1 at a time, place a rounded ⅓ cup of filling in the center of each tortilla. Roll into a cylinder and place in prepared pan, seam side down and close enough to touch. Cover the pan tightly with foil and bake for 30 minutes.
Stir taco sauce and sour cream in a small bowl. Spread over hot enchiladas. Sprinkle with cheese and cilantro and return to the oven, uncovered. Bake until cheese melts and sauce is bubbly (about 10 minutes).