If Sweden wins at Poltava, I think the war would have dragged on until another battle...and eventual swedish defeat. At least the war would be fought again in 10-20 years. The defeat would have only delayed to inevitable for some time, as Russia was becoming a powerful country and Sweden's power was slowing fading away.
Perhaps, if a Russian defeat at the Great Northern War, of which Poltava was a pivotal battle, a Swedish victory would inhibit the growth of Russian naval power since the Baltic was their best outlet at the time. (One assumes that if Russia lost the war, she would also have lost the majority of naval engaements as well.) It would also stifle Peter the Great's ambition to Europeanize western Russia, to make it more industrialized and more prosperous. Russia played a pivotal role in several European wars in the 1700's and early 1800's.
However, I think by far the most likely result of a Swedish victory at Poltava would have been that Charles XII would have continued the futile campaign in Russia, and get beaten the next year or the year after. But OK, there is a possibility that a Swedish victory could have resulted in a favourable peace treaty. In which case Sweden's demise as a major power in Northeast Europe would likely have been postponed to some other conflict in the not very distant future. Sweden stood straddled along Russia's path to European power status, and in terms of resources the odds were so heavily stacked against her that it seems diffcult to assume it was more than a matter of time. Short of Sweden defating Denmark so utterly that Denmark (and Norway) could have been absorbed into the Wasa kingdom, to say nothing of managing to make this more than a temporary affair and retaining the capacity to focus chiefly on outside threats (hardly a likely scenario), it's not easy how it would have been avoided.
Finally, you could annihilate Russian armies, but they would simply raise new ones. Charles' Army by contrast was possibly the best in the world at the time, but it was essentially irreplacable. One would think this might have told Charles that letting it wither away walking around Russia and Ukraine until Peter had a chance to trap it was not a very astute idea. When the sad remains of Dalkarlana, Närkeregementet, Livgardet and and the other famous regiments wandered off into captivity after Poltava, that was pretty much the death knell of the Swedish empire, whereas for Russia it would have been little more than a temporary setback had they lost.