Usually I'd just tell him NO when he goes for anything else, but he only eats the plants at night while I'm sleeping. I don't want to kennel him at night, but I'm not sure what else to do to keep my plants safe. (besides the obvious of moving the plant but this is a HUGE plant, and not moveable at night!)

If the plant is really that big you may want to purchase a wire puppy pen and put it around the plant to keep the dog away from it. You could also use a fireplace screen if it would be large enough to go around it to keep the dog away, even a baby gate may work depending on where the plant is located.

Some plants are toxic to dogs causing mild nausea or loose stool to being fatal. Please make sure this plant is not deadly and what to do if he does ingest some of it.

You may also want to consider moving the plant to a off-limit room.

I had a huge problem with one of my cats chewing on our wires which is extremely dangerous, so I had to figure out how to stop and the word no was not working. I bought a spray called bitter apple and it did keep her way for a while she did not like the taste, but once it wore off she was back to them again. Now this may seem mean to some people but it worked and she never chewed on them again and I didn't have to worry about my house burning down with her in it. I cut open a hot pepper and rubbed it along the wires and once she got a taste of that she didn't go near the wires again. Try the spray first see if that works, if not try the hot pepper it did the trick for me, some house plants can be poisonous for them so try to do something right away.

Spray the plants before you go to bed with Apple Cider Vinegar. I guarantee that it won't hurt the plants and the dog will stay away from them. Don't use commercial deterants for dogs, they are expensive and are not guaranteed to work.

Using a kennel at night might keep him safe? Also you can use small mouse traps that will snap and correct him. (only if he is large enough so they won't hurt him) A welcome mat turned upside down (the kind with the little plastic spikes that hold it in place) they also make little alarms that will sound off when he goes near them.

All good points written here, but it makes me wonder about your dog.
Dogs and cats both will eat grass for an upset tummy, and then throw it up of course.

You can buy grass seeds with a container for indoor use for animals. Try that for him. Any pet shop carries these kits.

Close off the room or you need to kennel the dog in another area.

Buy a dog bed and put it in your bedroom and let him sleep in there!

Spray bitter apple on them. It won't hurt the plants but it will make them taste awful.

The safest thing to do would be to kennel him what if the house plant is toxic to animals