No.

In Jain calendar terms:

• Poonam means Purnima — the full moon day.
• Chaudas means Chaturdashi — the 14th lunar day, usually just before Amavasya or before Poonam depending on the paksha.

So they are different tithis.

In simple words:

• Poonam = full moon
• Chaudas = 14th day

In Jain observance, both can be important for fasting and spiritual practice, but they are not the same.