Hi,
how did you mount the nfs shares in the end? If you went via browsing nfs via kodi, you could try kernel mounted (fstab)
But before you try that I would recommend adding a video caching to advancedsettings.xml.
Which pi are you using, if its a a pi3 I recommend these:
<advancedsettings>
<cache>
<memorysize>157286400</memorysize>
<buffermode>1</buffermode>
<readfactor>4.0</readfactor>
</cache>
</advancedsettings>
Thanks Tom.