Depends on a lot of things.
Are the clairvoyant and mind reader playing against each other or are they playing against an opponent without these sorts of powers?
If playing against each other, I can only see this comparison as fair if the mind reader can't simply copy the clairvoyant's ability to see the future by reading their mind.
If playing against regular opponents without powers, presumably we're talking about players at a much higher skill level in order to balance out the advantage of having future sight or the ability to read minds.
And finally, how good are either of these people at chess?
Ultimately I think the clairvoyant wins because being able to plan ahead is an invaluable skill in chess, whereas mind reading would only offer comparatively short term benefits.