chicken tacos in crock pot?

I was told cook the chicken breasts (cut and trimmed into strips) on low for 8 hours and high for 2-3... I've never made chicken in the crock pot (lame I know) I usually grill it but I really wanted to try a new recipe. I'm cooking them on high... so how long? And when should I add the fresh peppers and onions? I can't believe I've never used a crock pot before 😂