Heat olive oil in a skillet or aluminum slow cooker insert on medium-high heat.
Season one side of the chuck roast with 1/4 tsp. of garlic powder, salt and pepper to taste.
Place seasoned side down in skillet.
Season other side of roast with remaining garlic powder, salt and pepper.
Sear the first side for about 5 minutes, then flip.
Prepare marinade in a small bowl reserving water.
When roast is seared, transfer to slow cooker.
Pour marinade over roast and add 1/2 - 3/4 cup of water (enough to fill half way up the roast but not covering it).
Set slow cooker to low (8 hours).
When cooking completes, transfer to plate and shred with 2 forks.
Transfer to medium bowl and ladle juices over roast.
Assemble tacos or store in refrigerator until next day.
Enjoy!