Yes. Sports betting is a type of gambling which means winnings are fully taxable and must be reported on tax returns. Sports betting was legalized in 2018 through the repeal of PASPA and the taxing law hasn't changed because it's considered "gambling winnings."
Even if you don't live in a state where sports betting is legal, if you win, it's taxable income, which is what the IRS cares about. The biggest stipulation is that you only have to report your winnings if they are over $600 or at least 300 times the amount you bet. If you win more than that amount in person, you'll likely have to fill out a form at the sportsbook.
If you lose money, it may be tax-deductible, but you'll need to keep track of all bets. The key to receiving money is that you itemize deductions and keep detailed records of wins and losses. This is made easier by online sites which should keep a history of your bets.