Which Keisei train did you want to take?

The Keisei Limited Express for only 1000yen or the Skyliner for 1920yen? Either case, the PASMO card can be used.

At Narita Airport, if you buy a PASMO card from the PASMO machine, you can just go through the automatic gates, and get right on the Limited Express (no additional tickets required) to your final station.

If you take the Skyliner, you can use the PASMO card to go through the gates, and on the platform you can buy a Skyliner seat reservation from the Skyliner seat reservation machine, using a PASMO card as well.

But back to the main topic, if you plan on taking the Skyliner, then it doesn't hurt in my opinion to pay the few extra yen for the Skyliner and Metro pass. You can use it on 9 of the 13 - Thirteen "subway" lines in Tokyo that are operated by Tokyo Metro. For it's discounted price, its a pretty good deal even with that slight limitation. Though this package comes with a regular skyliner ticket and a metro pass, no PASMO, which means you'll probably have to buy a PASMO at the airport (and just not use it until later, or buy a PASMO and or Suica card later in Tokyo).

Or if you just want to save money, take the Keisei Limited Express for 1000yen.