The first steps one must take to successfully accomplish nail trimming-is the cat must be able to trust you to do so. He may already trust you in other ways but this can be a very sensitive issue for some cats. So can often take time.
To start, during cuddle time or when he is in a sleepy mood - slowly reach out to touch and gently squeeze his front paws. It may take a few attempts for him to allow this to happen - but after he has made the association you mean him no harm, he will allow this to continue. Start with a slow but quick touch and then gradually increase the amount of time you hold his paw. Provide treats during each time. When he is comfortable with your touch; place your fingertip to go in between his toes. Once he is comfortable with that, bring out the nail trimmer and show it to him. When he is looking at it - provide another treat.
*Demonstrate the use and sound of the nail trimmers by cutting a dry spaghetti noodle in his presence.
Once you sense he is comfortable with you touching his paws and the trimmers are not viewed as any threat - try cutting the nail. If there is success- provide treat. Even if you only manage to get one or two nails trimmed at a time - just try again tomorrow, keeping in mind which nails have been cut and which haven't.
With some patience and abit of time this should become an easier task for both of you.