Combine chipotle peppers, vegetable broth, fresh lime juice, granulated garlic, chili powder, cumin, and fine sea salt in a blender. Blend until smooth for about 30 seconds.

Heat a large skillet over high heat and add avocado oil. Once hot, add sliced portobello mushrooms in a single layer, searing for 2-3 minutes. Flip the mushrooms and sauté for another 2-3 minutes until golden brown.

In the same skillet, add another splash of avocado oil and heat. Add sliced red onion and bell peppers, sautéing for 6-8 minutes until nicely browned. Return cooked mushrooms to skillet and add fajita sauce, stirring for 1-2 minutes.

Warm corn tortillas in a dry skillet over medium heat for about 30 seconds on each side. Spoon the fajita mixture onto each tortilla and serve with preferred toppings.