Yes... this model (entity) you want to have normal map shader.
In his function/action write my.material = mat_nm;

something like this:
action my_player
{
player = me;
my.material = mat_nm;
..
...
....
}

But remember if this function/action is in other script than main.wdl, be sure that you have incuded nm.wdl before this script where this function/action is.