Combine the marinade ingredients in a large ziploc bag, add the chicken and refrigerate 8 hours or overnight.
Preheat and lightly oil your grill or a large sauté pan. Remove the chicken from the marinade, making sure no garlic or jalapeños are stuck to it. Grill or sauté over med-high heat until nicely charred and cooked through.
Let the chicken cool slightly while you assemble your taco toppings then slice the chicken into thin strips. Assemble tacos or let others make their own.