Begin by setting your Instant Pot to the "Sauté" function. Once it’s hot, pour in the olive oil. Add the chopped onion and cook for about 3-5 minutes, until the onion becomes translucent. Stir in the minced garlic and cook for an additional 30 seconds, allowing the garlic to become fragrant.
Next, add the ground beef to the pot. Break it up with a wooden spoon and cook until browned, about 5-7 minutes. Drain any excess fat if necessary. Stir in the Spike seasoning, dried Mexican oregano, ground cumin, and dried cilantro (if using), mixing well to coat the meat evenly with spices.
Add the drained and rinsed pinto beans, chicken broth, tomato paste, and petite diced tomatoes into the pot. Stir everything together, scraping the bottom of the pot to prevent sticking.
Seal the Instant Pot lid and set it to "Manual" or "Pressure Cook" on high for 15 minutes. Once complete, allow the pressure to naturally release for 10 minutes before performing a quick release for any remaining pressure.
Carefully remove the lid. Stir in the fresh lime juice and season with salt and fresh-ground pepper to taste. Serve hot, garnished with sliced green onions and chopped fresh cilantro. Optionally, add diced avocado on the side for extra creaminess.