It could be better, could be worse.
Certainly the excesses of the Cultural Revolution would not have scarred Tibet. Nor would the US back Tibetan uprising in the late 50s. However the Communists did somethings well that the Nationalists may not do.
The first is during the takeover in 1950. The Communist army was highly disciplined and managed to takeover with minimal bloodshed/destruction. The Tibetan people were well treated and things generally went smoothly. The Nationalists OTOH had been fighting a Tibetan invasion of Sichuan in the 30s and their expedition would certainly be headed by these old Tibet hands. Which probably would've led to violence and looting by the Nationalist troops from the beginning. If this mishandling triggers a revolt, the Nationalists can be quite ruthless, i.e. the massacre in Taiwan.
The second is the Communists made a lot of improvements to the lives of the Tibetan poor in areas of health care, education, land ownership. To this day it substantially subsidize welfare to placate the locals. OTOH the aristocracy and religious elites were targeted for destruction. The Nationalists would likely co-opt the elites and ignore the poor. Whether this would be a recipe for stability is unclear to me.