So long as nodes are added into Qlik Sense as hostnames, then the underlying IP address change should not have any effects. Validate this by going into QMC > Nodes and parsing the Host name column. It would likely be a good idea to flush DNS on the server (ipconfig /flushdns) and potentially reboot the server(s) after changing IP addresses to flush out any caching.
The real concern would be whether the subnet changes also imply new network topology / firewalls / etc. If there are issues, then do cross check the port requirements (https://help.qlik.com/en-US/sense/November2017/Subsystems/PlanningQlikSenseDeployments/Content/Deployment/Ports.htm) for Qlik Sense and ensure that there is open communication where needed for the environment. Since those changes can often take time for most organizations, noting that early on and getting the change request into the network teams' queue ASAP is important.