Only taxable compensation can be used to fund an IRA. Gambling winnings are not taxable compensation unless you are self-employed as a professional gambler.
See this IRS website for IRA contributions - https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-ira-contribution-li...
Also see IRS Publication 590-A for a definition of compensation - https://www.irs.gov/publications/p590a/ch01.html#en_US_2016_publink1000230355
