This article from the US Conference of Catholic Bishops talks about the work of the joint PNCC-RCC commission. One of the issues discussed was of the sharing of ministries and licensure of clergy within the military chaplaincy. Very good idea.
As most people know the PNCC are listed in the Catholic Missal as a group able to receive communion. They have valid apostolic succession and sacraments. They achieved some limited inter communion due to Pope John Paul the II (obvious reason).
Here is a Youtube video about them. youtube.com/watch?v=bkllZ_O1JaU
Wiki article. en.wikipedia.org/wiki/Polish_National_Catholic_Church