thanks for your advise Islanders
Even though you have open work permit, some province employer might report it to the office immigration in your province that you left the employment which support you for the PNP. If they report you, there is a chance your nomination get cancelled and so does your PR application.
For example; I have friend here, with PGWP which is open, have a fulltime job and apply for PNP. The office immigration send an email to her employer, to confirm if candidate leave the employer after get the nomination certificate must be report it then they will cancel the nomination.
I am sure some province have each rules, so you better be careful
Good Luck