Heat 1 tbsp (15ml) of olive oil in a large skillet over medium-high heat. Season your 1 lb (450g) of chicken breasts evenly with 1 tsp (5g) each of salt and black pepper. Place the chicken in the hot skillet and sear until a deep golden-brown crust forms, about 6-7 minutes per side. Once cooked through to an internal temperature of 165°F (74°C), remove from heat and shred the meat using two forks.

In a medium mixing bowl, whisk together 2 cups (480ml) of salsa verde and 1/2 cup (120ml) of sour cream until completely smooth and a pale green color is achieved. Take 1/2 cup (120ml) of this creamy sauce and toss it directly into your shredded chicken to keep the filling moist. Reserve a small portion of the remaining sauce in a side bowl for serving later.

Preheat your oven to 375°F (190°C). Lightly coat the bottom of your white ceramic rectangular baking dish with a thin layer of the creamy green sauce to prevent sticking. Lay out your 8 tortillas and distribute the saucy shredded chicken evenly among them. Sprinkle a small pinch of your 2 cups (200g) of Monterey Jack cheese inside each, then roll them tightly and place them seam-side down in the baking dish.

Pour the rest of the creamy salsa verde evenly over the rolled tortillas, ensuring the edges are coated so they do not dry out. Generously top the dish with the remaining shredded Monterey Jack cheese. Bake uncovered for 20-25 minutes until the sauce is vigorously bubbling around the edges. Switch the oven to broil for the last 2-3 minutes until the cheese is slightly browned and blistered.

Remove the baking dish from the oven and let it rest for 5 minutes so the creamy sauce can set slightly. Garnish the top generously with 1/4 cup (15g) of fresh cilantro leaves, 1/4 cup (40g) of finely diced red onion, and vibrant sliced rings from 1 medium (15g) jalapeño. Serve warm with the extra small bowl of creamy green sauce on the side.