I’m no authority on this, but I’d say it depends on the experience. There are many saints who’s last words were about seeing different heavenly things. If that’s counts as a near death experience then I’d say the Church approves of them at times.
However, people who were technically dead, and claim to have been to heaven or even hell and take different truths back with them…I’d say those are nearly universally rejected.
There are a few people in histroy, mystics and Saints, who God gave visions too and the Church has appoved some of those, so it’s not like it can’t happen, but it’s all at God’s discretion.
People who were recusitated by CPR or who’s hearts were shocked back into activity, God isn’t fooled into thinking they’re done with Earth. Thus, only those He has reason to give a sight of Heaven or Hell with have it revealed.