Is it possible to use the Shape Water spell to control the water generated by the Tidal Wave spell?
The tidal wave spell has a duration of instantaneous, and ends with this sentence:
The water then spreads out across the ground in all directions, extinguishing unprotected flames in its area and within 30 feet of it, and then it vanishes.
So no, you can't use shape water on the water from tidal wave, because there is no point in time where that's possible. Even if you readied an action to do it, reactions take place after their triggers, so the water will still be gone at the point when you cast shape water.
Rule as written, it seems difficult
As Miniman already stated, the effect of Tidal Wave is Instantaneous and the water vanish at its end. Shape Water having a casting time of an Action, only a Ready action could allow to use it in this case.
I said "could" because the choice of the trigger for the Ready action seems difficult :
If you choose "when X is casting Tidal Wave", the trigger would be the same as a counterspell : the spell wouldn't be cast yet and there would be no water to shape.
If you choose "when Tidal Wave is cast", you would cast your spell after the trigger happened and, since Tidal Wave is instantaneous, the spell effect would already have resulted and the water vanished.
A dark wanderer under another response suggest "when water appear", stating that there is a sequence of event in the spell description. I guess this is technically possible but even if the DM allow it, the effect would be minimal : the sequence is "water appear doing damage" then "water vanish" so you would be able to manipulate the water only after the damage done.
As a DM, I would certainly allow it to reduce the damages with a contest of spellcasting check against the caster.
Shape Water does not require the water it affects to be non-magical. While it would require a readied action, casting Shape Water on the water created by a Tidal Wave spell is not only possible but also would allow you potentially protect some unprotected flames from being extinguished by ensuring they were not within 30' of the water created by the spell, since in is, in fact, that water's area and not the spell's which determines the radius unprotected flames are extinguished in.
Note, however, that the actual damage the spell deals is completely disconnected from the water it creates and so, while you could absolutely avoid getting hit by the water from the spell with a well-timed freeze or flow-reversal or whatnot depending on environmental circumstances you would still be subjected to the massive bludgeoning damage from the spell since, again, that has nothing to do with being hit by the water under the text of the rules. You may well be able to argue that preventing the water from hitting you should prevent the damage, however, depending on the style of your DM.