I myself wouldn't bring vape gear into Singapore. Fortunately, I visited already (as a child) and it's an interesting country, but not a vape friendly country... At all. I'm also not sure on the status of other nic replacement strategies, but if you must travel there, I'd probably recommend using something like Sweedish snus or nic salt pouches, which are at least disposable.
I will point out AND SHOULD POINT out that I don't know their "legal" status, so I'd probably research which (if any) OTC nicotine containing prescription aids and what not are "permitted" or not, but I would most definitely NOT recommend trying to bring vape gear of any sort.
Best of luck,
Anna