Yes, you can do that or, as Aditya Somani, explained simply stay in the Netherlands.
If you enter Italy after December 1st, you won't receive a visa but simply make use of the 90-day visa-free stay granted to US citizens. This is possible because the time spent under a long stay visa do not count towards the 90-day limit. If it did, it would not be possible to enter the Netherlands either.
The official source for this rule is article 5 of the Schengen Borders Code:
- For intended stays on the territory of the Member States of a
duration of no more than 90 days in any 180-day period, which
entails considering the 180-day period preceding each day of stay, the
entry conditions for third-country nationals shall be the following:
1a. For the purposes of implementing paragraph 1, the date of entry
shall be considered as the first day of stay on the territory of the
Member States and the date of exit shall be considered as the last
day of stay on the territory of the Member States. Periods of stay
authorised under a residence permit or a long-stay visa shall not be
taken into account in the calculation of the duration of stay on the
territory of the Member States.
(b) they are in possession of a valid visa, if required pursuant to Council Regulation (EC) No 539/2001 of 15 March 2001 listing the third countries whose nationals must be in possession of visas when crossing the external borders and those whose nationals are exempt from that requirement, except where they hold a valid residence permit or a valid long-stay visa;
The second paragraph explains the visa types that are applicable under this rule.