I also got NOI from Onrtario with CRS 436 (NOC 2172, highest qualification Bachelors). I am considering applying for OINP since in March my CRS would drop to 431.
BTW, as SweetGurl said,
Can you kindly point to any official resource where it mentions that you can freely return to accepting ITA from Express Entry pool. I'm confused since the letter I received mentions:
If you accept a nomination, you are indicating to both Immigration, Refugees and Citizenship Canada (IRCC) and that provincial or territorial jurisdiction that you intend to live in that province or territory and that you will comply with any other provincial or territorial program requirements.
Once you accept a nomination, your profile will no longer be visible to other provinces and territories, so you will not be considered for nomination by other jurisdictions. You will also not be considered for federal economic programs in Express Entry.
If a province or territory nominates you and you decline the PNP nomination, you will not be invited to apply under Ontario's nominee program.