Except for a chain leash (which is super uncomfortable to use and can be heavy on a smaller/medium sized dog), he'll eventually be able to chew through anything. I find braided leashes tend to last longer, but unless you can train him to stop, you're just going to keep buying new leashes.
If the dog things you trying to stop him from chewing the leash is a game, you're definitely approaching it wrong. Have you considered taking him to puppy or dog obedience classes, even basic ones? If you're not a good trainer, they will help you a lot with that and other issues.
If he tugs on the leash, you need to stop walking him, and instead of trying to pull the toy out of his mouth, just turn away from him and ignore it. The first few times he might be chewing/pulling for a few minutes, but he'll soon start to look at you like "uh, why aren't we moving?". If you do this enough, he'll learn that chewing or biting on the leash means the walk stops. If you try to stop it by pulling the leash out of his mouth, pushing him away, or trying to tell him to stop or distracting him, he's going to think it's a game and that it gets him some attention. It's ok to say "NO", but keep the command short and simple and don't keep repeating it.
Will he carry a toy in his mouth? You can bring a stuff or a ball on walks and give it to him to hold whenever he grabs the leash, as well.
Walking him on a harness may improve it because the leash isn't as close to/dangling in his face, but he still might turn around and jump to grab it. I also wouldn't recommend this for a dog that pulls.
How old is he?