Hi @kem104,
Thank you for posting in this community.
I tested Patch fox's answer and successfully changed the URL and name of the List.
I'm guessing your last null-value expression in a method problem is due to your $list being null, please double-check the URL and name of your current list before re-running the power shell.
Attached below is my PowerShell and test results (in my case changed list1 to listA)
#SharePoint online site URL
$siteUrl = "https://tenant.sharepoint.com/sites/24July"
#Current display name of SharePoint list
$oldListName = "list1"
#New list URL
$newListUrl = "https://tenant.sharepoint.com/sites/24July/Lists/listA"
#New display name for SharePoint list
$newListName = "listA"
#Connect to SharePoint online site
Connect-PnPOnline -Url $siteUrl -Interactive
#Get the SharePoint list
$list = Get-PnPList -Identity $oldListName
#Move SharePoint list to the new URL
$list.Rootfolder.MoveTo($newListUrl)
Invoke-PnPQuery
#Rename List Set-PnPList -Identity
Set-PNPList -Identity $oldListName -title $newListName
Here is my result:
You'll notice that the name on the side navigation bar hasn't changed, but you can click Edit below and rewrite the name on the quick navigation bar.
Hope this information helps.
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