Newfoundlands are great dogs. I only know a little about your situation but here are a few tips that should help until we can get together in person.
Much like a Retriever, Newfoundlands are what I call mouthy dogs. Just by their DNA they seem to always need to have something in there mouth.
I don't know if you drink bottled water or not but an empty 16 oz. plastic water bottle is a good tool for this task.
Every time you catch Coco (I hope I got the name right) chewing on something, redirect his/her attention with the water bottle (lid on tight with just a dribble of water in it.) Squeeze and crackle it to make it interesting. Leave a couple of bottles around in the open where the dog hangs out. The bottles are better and more interesting than a bought chew toy.
