Because you layer this Tex-Mex dish, lasagna-style, instead of rolling each enchilada individually, you save time in the kitchen, and the results are ultimately healthier because the tortillas don't have to be fried or softened in oil before you assemble the casserole. Look for Mexican crema at Latin food markets or with the Mexican cheeses in the supermarket.
Place a small roasting pan in oven. Preheat oven to 425° (leave roasting pan in oven as it preheats).
Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Sprinkle both sides of chicken evenly with cumin, salt, and pepper. Add chicken to pan; sauté 3 minutes. Turn chicken over, and place in the preheated roasting pan. Add onion, garlic, and tomatoes to pan; bake at 425° for 15 minutes or until chicken is done. Cool. Shred chicken; toss with tomato mixture.
Combine 3/4 cup cilantro, juice, and salsa verde; spread 1/4 cup salsa mixture in the bottom of an 11 x 7-inch glass or ceramic baking dish coated with cooking spray. Top with 4 overlapping tortillas, half of chicken mixture, and 1/4 cup salsa mixture. Repeat layers. Top with remaining 4 tortillas and remaining salsa mixture; sprinkle evenly with cheese. Bake at 425° for 15 minutes or until golden; sprinkle with remaining 1/4 cup cilantro. Top each serving with 1 tablespoon crema.