Breastfed babies do get more nutrients that helps to support the babies brain health and development and studies have shown that kids and teens that were breastfed as babies do tend to have a higher IQ and do tend to be smarter than those that are formula fed.
There's no guarantee though that just because a baby is breastfed instead of formula fed that the breastfed baby will be smarter.
But a breastfed baby will typically have a healthier brain and better overall health and also be less prone to infections and disease or other illnesses.
Breast Milk from the mother's breast is always the best milk to feed your baby.
So if possible breast feed the baby at least part of the time because the baby will likely be much healthier and may be smarter than those formula fed babies.