Add beef to slow cooker along with onion, garlic, lime juice and spices then top with broth
Cover and cook on low for 8-10 hours until meat shreds easily with fork. If it doesn't shred, it need to cook longer
Cook rice according to package directions (Optional, add some fresh chopped cilantro and lime juice to the cooked rice for more flavor)
Serve on tortillas topped with rice, beef, and pico. Roll up tightly to serve
Notes
The beef can be made up ahead of time with the onion, garlic, lime juice and spices and then stored in a plastic zippered bag in the fridge for up to two days or freezer for up to 3 months.