Amphetamines are scientifically proven to do this, they're actually issued to military pilots. Closely related is methylphenidate otherwise known as Adderall. If you're OK purposely setting out to use one of the most addictive drugs out there (nicotine), why not use a drug purposely made for the application that's been proven to work and whose side effects are known?
I probably would not mind trying it, but I would have a hard time obtaining it legally.
Regarding nicotine and addiction - I believe the habit is just as addictive as the nicotine itself? I stopped cold turkey on the nicotine gum a year back. Never really had any problems with it.
I did however have challenges quitting the cigarette back in the day, but when I finally quit I was off nicotine for 10 years and have not smoked since.
Anyway, I don't really feel any special benefits from the nicotine. I originally used it to curb apetite/hunger when dieting and because it CAN help weight loss on its own. I have not noticed any cognitive effects that's worth mentioning. But it can be a nice reward when sitting at the computer for long hours as it IS stimulating in a pleasant way most of the time.
Alternately, might be worth taking a look at priorities and if putting yourself in a position working hours that continuously require chemical assistance to maintain is really worth it in the grand scheme of life? Absent my family starving I can't think of a situation that would warrant that, and even then it would only be a means to the end of eliminating the need for such extreme measures as soon as possible.
I think most people who've accomplished great things have done great sacrifices and put in the hours. If you don't put in the time, you'll never earn a dime, right?
I'm on my own now, so don't have luxury of a stable income otherwise, so I need to make sure I make the most of what time I have.
I don't need chemical assistance. Would just be interested if there's something that can help alleviate the burden of long work hours.

I'm eating healthy and working out on a daily basis, so that definitely helps health wise.