I'm just concerned if any pesticides/alcohol might damage my board.
I think Alcohol is fine compared to pesticides mate because alcohol is wont leave any stain inside your board not like pesticides that has other compound that may harm your internals.
Just like what @peter0425 says make sure to Blow air right after you sprayed so it will dry faster and also take the plug first before doing such.
I have same problem in my laptop's keyboard in last year and this is what i did luckily they all died and never comes back again maybe because of the scent of alcohol that remains inside.
It seems like a lot of people have tried with alcohol and I will give it a shot. Thanks for your suggestion mate. I'll try it with thinner or sanitizer.
That's disgusting.
I haven't seen anything similar.
Probably your laptop was so dirty that ants found home in there.
Just throw your laptop in rubbish and buy a new one but try to keep it clean.
Well, I don't really think I should throw away my laptop in trash just because it has ants

I have a bad habit of eating cookies, chocolates while I'm working on my laptop and most of the times, I do not brush my hands before typing onto the laptop. I think that is what made the debris settle into the laptop from the small gaps in between the keyboard and that made ants attack my laptop.
I am probably not going to throw my laptop only because of this issue lol. But yet, thanks for your suggestion.
Luckily you know the real reason why this is happening.
I it a matter of health. Those ants might be infected or they might be carrying diseases and still they are walking and dying in the same place you put your fingers. Then you put your fingers in your mouth.
Realising the truth, ants are most hardworking creature on this planet. They also are hygenic /clean creature which will not destroy my laptop and I know it. Also so far, there is no news or nothing related to ants spreading any kind of disease. Ants are common. You are reacting to ants like those are some huge pandemic spreading illness or any kind of virus.
Speaking truth, I do not care if they are spreading any virus or anything but what I am ONLY concerned is about taking them out from my laptop forever.