after navkarshi time can i take muthsi pchkhan and not navkarshi because i have eaten late night

Yes, if Navkarshi time has already passed, you should take the panchkhan according to the actual time you are taking food or water — not Navkarshi.

In Jain practice, Navkarshi is only for when food or water is taken after Navkarsi time and within the proper rule of that vow. If you have eaten late at night and then the next morning the Navkarshi time has already passed, then Navkarshi is no longer the correct panchkhan. You should take the panchkhan that matches your current observance and timing.

Important point:

• Do not take a wrong panchkhan just by name.
• Take only the vow that is valid for that time.
• If you are unsure, follow the guidance of your Guru Bhagwant or local Jain tradition, because there can be small differences in practice.

So in simple words: After Navkarshi time, do not say Navkarshi panchkhan; take the appropriate panchkhan for that time instead.

If you want, I can also explain the difference between Navkarshi, Porisi, Sadha-Porisi, and Porsi in simple Jain terms.