Dice the yellow onion, slice the bell peppers into thin strips, and chop the zucchini into bite-sized half-moons.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until shimmering.
Add the ground beef to the skillet, breaking it apart with a wooden spoon, and cook until browned and no longer pink.
Stir in the diced onion and bell peppers, sautéing for 4-5 minutes until the vegetables begin to soften and caramelize.
Add the zucchini along with the chili powder, cumin, smoked paprika, garlic powder, onion powder, sea salt, and black pepper.
Toss everything together to ensure the beef and vegetables are evenly coated in the spice mixture, then cook for another 3-4 minutes until the zucchini is tender-crisp.
Remove the skillet from the heat and garnish with fresh avocado slices before serving warm serving.