Yes, my PR is still in process, 120+ days. I had mentioned the same to SINP that my nomination is about to expire and the application is still not finalized. they responded after my second reminder email that its now extended for another 3 months and that's how they do it, 3 months at a time and only twice.
There is a form and a process to follow for extending nomination.
Details in the link https://www.saskatchewan.ca/residents/moving-to-saskatchewan/immigrating-to-saskatchewan/saskatchewan-immigrant-nominee-program/sinp-procedures-and-guidelines/amendments-to-a-sinp-nomination