It is on top of the 0.75% APR, but that's a terrible return on your money compared to other bank account bonuses. You can always find coupons for Chase Total Checking signup bonuses of $300. Here's
one. (There's a savings account bonus too but the % return is lower. If you have the money for that one - as I assume you do since you're considering a $50k one - then go for it).
For the checking account bonus you're going to need to maintain $1500 in the account for 6 months to avoid fees, but that's a 20% return in six months, compared to capital one's pitiful 1% return in 90 days.