Maybe Normal dual typing is becoming more of a common thing?
In Gen VI we got Helioptile/Heliolisk as the first Normal/Electric Pokemon and then Litleo/Pyroar as the first Normal/Fire Pokemon. Perhaps Nekkoala will keep its Normal typing but gain a secondary type alongside it.
It is cool how we're getting more interesting dual-types for Normal so maybe the Nekkoala evolution could have a possibility to gain a secondary type. Fighting-type could actually go well, since we haven't gotten a natural Pokemon of that typing yet, because currently it belongs to a Mega and an alternate forme.