Preheat your oven to 200°C (390°F).
Lay the chicken breasts flat on a cutting board and use a sharp paring knife to carefully slice horizontally into each, creating a pocket without cutting all the way through.
In a bowl, combine the spicy chorizo, grated cheese, smoked paprika, chopped herbs, lemon zest, minced garlic, salt, and pepper. Mix until well blended and fragrant.
Stuff each chicken pocket generously with the chorizo mixture, pressing gently to pack the filling inside.
If needed, secure the openings with toothpicks to prevent the filling from escaping during cooking.
Heat olive oil in an oven-safe skillet over medium-high heat until shimmering and fragrant. Carefully place the stuffed chicken breasts in the skillet and brown for 3-4 minutes per side, until golden and crisp.
Transfer the skillet to the preheated oven and bake for 20-25 minutes, or until the internal temperature reaches 75°C (165°F) and the juices run clear.
Remove the skillet from the oven, take out the toothpicks carefully, and let the chicken rest for 5 minutes. The filling should be bubbling and cheese melted inside.
Squeeze fresh lemon juice over the chicken for a bright finishing touch, then serve hot with your favorite sides.