The ctzp law won't allow one to take their capital from selling properties legally. There are already laws against such activities and they will remain as they are. Yes, people might try illegal ways(not necessarly unethical tho since it's their property) but that is already happening currently and recenty with tight watch from Nepali authorities few are getting busted too.
I think this law gives incentives to keep NRN properties in Nepal and motivates NRN to do productive things with them by bringing new investments. If there are no legal rights for NRNs to maintain their properties then they are forced to do legal/illegal stuffbto bring their money where they reside permanently. At the end of rhe day its their money. As long as it wasnt earned by illegal means they should be able to do whatever they want with it.