Is it ok to chew a peice of nicotine gum during a long shift at work?

i don't plan on quitting smoking anytime soon yet. but i have to work a 8 and a half hour shift today. so i have to go 4 hours without a cigarette. i don't want to get agitated or get mean to customers so im wondering, is it safe to chew a piece of nicotine gum to keep my sanity?