Can Gust return a token unit?

Yes, Gust can target and return a token unit to its owner's hand, provided that token unit meets the requirement of having 3 Might or less and is located at a battlefield.

However, once the token unit is returned to the hand, it will cease to exist. According to Rule 183.1, if a token is put into any non-board zone (such as a hand), it ceases to exist immediately after moving to that zone.

It is important to note that this process does not count as the unit "dying." Because the unit is moved to the hand and then ceases to exist, it does not trigger any "when a unit dies" abilities (as confirmed by RiftJudge FAQ #4395 and #5180).