Heat olive oil in a large pot over medium heat until shimmering, then sauté diced onion until softened, about 5 minutes, stirring occasionally as it turns translucent. Add minced garlic and cook for 1 minute, stirring, until fragrant and lightly golden at the edges.

Pour in chicken broth, diced tomatoes with chiles, and red enchilada sauce, then stir well until the mixture looks evenly red and glossy.

Add shredded chicken, cumin, and chili powder, stirring until the chicken is coated in the spice broth and the surface shows small bubbles starting around the edges.

Bring the soup to a simmer and cook for 20 minutes, stirring occasionally, until slightly thickened and the flavors look blended.

Season with salt and pepper to taste, tasting and adjusting until the broth balances savory and heat.

Ladle the soup hot into bowls and top each serving with tortilla strips, shredded cheese, cilantro, avocado, and fresh lime juice, so the cheese begins to melt from the steam.