Cook mushrooms in a single layer in a dry skillet over medium heat for 2 to 3 minutes to release moisture.
In a food processor, blend cream cheese, 1/3 cup sour cream, 2 chipotle peppers, and 1 teaspoon cumin until smooth. Add mushrooms, spinach, and colby jack cheese, pulsing to combine.
In batches of 4, spread tortillas out on a microwave-safe plate. Cover with a damp paper towel and microwave for 30 seconds. Take out of microwave and remove one tortilla at a time from plate. Place filling on one end of tortilla and roll tightly, careful not to overfill.
Place seam-down in a 9 x 13-inch baking dish coated with cooking spray. Repeat with remaining tortillas and filling. Spray top of taquitos with cooking spray. Bake 13 to 15 minutes or until golden brown and crispy.
To make dipping sauce, chop remaining two peppers and combine them with remaining 1/2 cup sour cream, 1/4 teaspoon cumin, cilantro, lime juice, and garlic powder. Serves 4 as appetizers, 2 as a meal.
Per appetizer serving: 496 calories, 27 grams fat (17 grams saturated fat), 45 grams total carbs, 8 grams fiber, 21 grams protein