Since I had PCOS and a risk of high blood sugar, my doctor told me to limit high-starch foods like potatoes. If you don't have gestational diabetes it is fine in moderation, but do monitor your sugar levels.
Yes, simple boiled potatoes are great for energy and easy on a nauseous stomach. Just avoid heavy oily french fries or chips, and if you have extreme bloating, ask your doctor.
Eating for three meant I survived on mashed potatoes in my first trimester! It was literally the only thing that didn't make me throw up, so go ahead and enjoy it.