I worry about quitting smoking though because NoFap is stressful enough and quitting smoking will make me feel worse. They say it's a bad idea to quit too many things at once.
That's true. Trying to correct your life in one big step instead of a few smaller ones is difficult or even impossible. What I intended with my previous post was that you could try to improve other areas and give NoFap a break.
If you, however, want to continue with NoFap, I can give you some tips that have helped me during my journey. I bet you're aware or even applying some of these, but at least I can give you a good reminder.
1. Quit using social media platforms. They contain a lot of content that can be described as "triggers" for some NoFappers. Now, I don't mean you should delete them if you're really passionate about your profiles. Just cut down the time spent and maybe block sites that contain erotic images or somehow act as triggers that lead to PMO.
2. Like Pegasus said, increase training. Do you have a gym membership? Or maybe you have a big swimming pool that you can use. It's important, that you have a direct plan what you're going to do when you feel the urge. Physical activity requires time; at least for that 1-2 hour window you would be unable to fap.
3. If you already trained or it's rest day, you can contact your friends or family members. Maybe ask your old friends to go for spontaneous fishing trip or maybe you could watch some football with them?
4. Stay focused. If you find yourself surfing the internet for porn or such things, just close your device or at least close the browser. If you find urge to fap during PE exercises, try to count the reps of the exercises you're doing. Or alternatively, time. That way, you're more focused on the exercise than the urge. What worked for me was having small pauses during exercises. That could work. Maybe get a glass of water and continue later?
Hope some of these work for you!