In a skillet, heat olive oil over medium heat. Add diced onion and minced garlic, sauté until fragrant and onion is translucent. Add chicken breasts, season with salt and pepper, and cook until fully cooked, about 6-7 minutes per side. Remove from heat and shred the chicken.

Mix Filling

In a large bowl, combine shredded chicken, green chile sauce, black beans, cooked rice, shredded cheese, and chopped cilantro. Mix well to combine.

Assemble Burritos

Lay a tortilla flat and place a generous scoop of the filling mixture in the center. Add a dollop of sour cream on top. Fold in the sides and roll up tightly to enclose the filling. Repeat with remaining tortillas.

Heat and Serve

In a clean skillet, place the burritos seam-side down and heat over medium heat until golden brown and crispy, about 2-3 minutes per side. Serve warm with extra green chile sauce and sour cream on the side.