Isn't that Togashi did not provide any solid proof in the Manga or in the OVA adaptations that the late Chairman is indeed an Enhancer type?
so take a look and read some key points here:
1. It is already stated that a person's Nen is directly corelated and equal to their attitude, behavior and overall personality - Chairman Netero did not show any notable characteristic as an Enhancer. Instead he choose Pariston as his second in command and he is noted a a notorious twisted man - which imply as a natural "Emitter" type.
2. Meruem stated that Netero simply immersed in his Nen training, dedicated himself in martial arts so much that he maxed his overall Nen potentional.
3. Set of skills. Netero, instead of developing any Enhancer Nen Skill, he develop skills that it from Emission and Manipulation. Being called as one of the best and strongest Nen User before, isn't too dumb and stupid for our oldman to choose his Nen abilities contradicting his natural type?
4. not to mention, his final skill is........... "Zero No Te" - Emission.
If what they all said is true, that based from some playing cards that Netero is an Enhancer then he is just a one dumb and idiot Nen user. That may be the reason why he failed to match Meruem. Sad life. Lets agree to disagree.
I think Netero was born as a pure enhancer, using his nen to boost and complement his marital arts throughout the first 46 years of his life. However, once Netero completed his punches of gratitude over the years a change occurred. His obsession and commitment to complete his 10,000 punches a day for the next four years transformed his nen and how it could be used. The 100 type Guanyin is a miracle of nen where Netero can emit an enhanced symbol of his faith and can be used as an extension of Neteros abilities. He’s not dumb like kastro in that he’s still an enhancer but is a true master of nen who can properly balance using emission and enhancement without any disadvantages. Similar to how Zeno emits his aura and manipulates it to move and take the form of dragons. Even hisoka who mastered his transmutation type nen may have used emission to “project” his bungee gum, or it may just be the properties allow him to do that. Nen is too complicated to have absolutes I guess is what I’m saying.