@maple Nando's is a chain restaurant over here that serves piri-piri style chicken dishes

"cheeky" is an adjective in this case referring to something you shouldn't really do but you're going to anyway

like you might go for a cheeky pint after work, you shouldn't really be straight off to the pub but you'll do it anyway

combine the two and you get a cheeky nandos, you shouldn't really be eating out for the nth time this week but you'll do it 'cause it's cheap and you're lazy