The Music folder in a fresh Ubuntu installation is configured as a special user folder, an XDG user dir. You can see that from the music emblem on the folder icon. After your action, i.e., deleting the folder, and replace it with a symbolic link, the link will not have that status anymore: the folder icon of your link will not have the music emblem.
You can return the special status to your link by editing your user configuration file
~/.config/user-dirs.dirs. After that, it will acquire the music emblem on the folder.
Whether there will be problems actually depends on the applications you want to use and how they are configured. If you use other apps, and you do not want them to interfere in the folder where your Music symbolic link refers to, then it is probably wise to use another name for the link to your ~/NextCloud/Music folder, and leave another Music folder in place as the XDG folder. Alternatively, you will need to configure the other app to look elsewhere, if the app allows that.