You have to get some Bitter Apple spray and spray the cords or whatever else you see her chewing on. If you catch her doing it, say NO firmly (don't yell) and then re-direct her attention by giving her something safe to chew on. You will need to get LOTS of chew toys while she is a puppy, lol. Then when she begins to chew what you WANT her to, tell her GOOD GIRL and give her pats and praise.
She'll get it!