The US Department of Defence has "announced a near doubling of its list of recognized religions. It will now formally recognize humanism and other minority faiths among members of the armed forces."
The list now encompasses humanism and Asatru, a religion which focuses on the Norse gods of the Viking era. This announcement means that "servicemen and women who are adherents of small faith groups are now guaranteed the same rights, privileges and protections granted to their peers who are members of larger faith groups."
This announcement does not necessarily mean that chaplains associated with these faiths will follow, at least not in the near future, but it does open the door to that possibility. In the Canadian context which I am familiar with, a faith group must have structures which allow for the recognition and accountability of persons who can perform the general functions, such as counselling, expected of a chaplain, and who have a religious organization to which they are accountable. Not all faith groups produce clergy or clergy equivalents in the way that, say, Christianity, Judaism and Islam do.
That being said, I have Canadian chaplain colleagues who have served with Dutch humanist chaplains and found them professional, dedicated and caring, which is perhaps all that many military personnel want of a chaplain.