Preheat the oven to 400°F. Lightly spray a 9x13-inch baking dish with nonstick cooking spray. Set aside.
In a large bowl, mix together the shredded chicken, diced jalapeño, taco seasoning, sour cream, cheddar, Monterey Jack, and green chilies until well combined. Set aside.
In a medium saucepan over medium heat, combine the cubed Velveeta and the undrained diced tomatoes with green chilies. Cook, stirring occasionally, until the cheese is melted and the sauce is smooth.
Spread 1 cup of the queso mixture evenly into the bottom of the prepared baking dish.
Lay a tortilla on a flat surface. Spoon about ½ cup of the chicken mixture into the center. Roll tightly and place seam-side down in the prepared baking dish. Repeat with the remaining tortillas.
Pour the remaining queso mixture evenly over the rolled tortillas, spreading to coat them fully.
Bake uncovered for 15 to 20 minutes, or until the dish is heated through and the cheese is bubbling around the edges.
Remove from the oven and let cool slightly. Garnish with diced tomatoes, sour cream, extra jalapeño, and chopped cilantro, if desired.
Serve warm.