Generally speaking, the size of you wager should not influence your odds of winning at pokies. That being said, some pokies machines do alter the paytables and odds depending on your wagering amount but this will clearly be stated.
Players should consider that many online pokies have multiple paylines and the more paylines you play, the more you will have to wager. Naturally, if you want to maximise you chances of winning you will need to play all the paylines and therefore wager more. In this instance, it’s more that you need to wager more to be able to win, rather than to increase the odds.