Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Slice the red bell pepper, yellow bell pepper, and red onion into thin, even strips.
Toss the peppers and onions on the baking sheet with 0.5 tablespoons of olive oil and a pinch of sea salt.
Roast the vegetables for 15-20 minutes until they are tender and show slight charred edges.
While the vegetables roast, slice the chicken breast into thin strips and season them with sea salt and black pepper.
Heat the remaining 0.5 tablespoons of olive oil in a large skillet over medium-high heat.
Add the chicken to the skillet and sauté for 5-6 minutes until golden brown and cooked through, then set aside on a plate.
In the same skillet, add the sliced cremini mushrooms and cook until they release their moisture and turn a deep golden brown.
Add the minced garlic and fresh thyme to the mushrooms, sautéing for about 1 minute until the aroma fills the kitchen.
Return the roasted peppers, onions, and cooked chicken to the skillet, tossing everything together.
Drizzle with balsamic vinegar and cook for an additional 1-2 minutes to glaze the ingredients and serve warm.