Generously salt and pepper both sides of beef. Set the instapot to the Sear/Brown setting. (If using a traditional slowcooker, heat a large skillet over medium-high heat.) Once hot, add the beef and sear until brown (2-3 mins). Turn over and sear another 2-3 mins. Remove from heat and set aside. (If meat won't all fit into the pan, do in 2 batches.)

Add 1 cup of beef broth to the pan to deglaze, scaping up any stuck bits. Change setting to Slowcook (or reduce heat to low). Add remains beef broth and rest of ingredients. Stir until well combined.

Add beef into slowcooker and stir to coat with liquid. (If using traditional slowcooker, place beef in slowcooker and pour the liquid from the skillet over the beef.)

Slowcook on low for 8 hrs (or high for 4 hrs.)

Once cooking is complete, shred beef with 2 forks. If you like a finer shred, a potato masher works great.

Serve immediately.