Hey Chris, the behavior you experienced is expected. VMFS Datastore names are defined in Vmware, not on the storage subsystem. For example, below I have created a new volume on the Nimble array named "Test". When I scan, the disk shows up with the eui and the path id (Iqn). You can see the name of the volume embedded as part of the IQN.
After adding the disk and selecting VMFS 5, I verify the device and capacity.
When I click next, I am asked to name the Datastore in VMware. Note that the name is not inherited from the eui or path id from the storage subsystem. I must name the datastore in Vmware.
I can also right click on an existing datastore and select "rename". That is the task I believe you want to do if you are looking to rename an existing datastore to match the name on your Nimble.
I hope that helps!!