Personality:
Before Nolan met Colt he wasn't exactly the same person, he lived for the thrill of adventure and action, he had little regret for using his power wildly and would fight anyone he thought worthy to fight, most likely to the death, he wanted nothing more than to grow his power and get kicks out of using it to fill his thirst for action, and desire to feel like a 'hero'.
But as he discovered the true nature of Current, and met his new apprentice Colt, he had a change of heart, he had a friend now, he couldn't afford to endanger him while both of them still had things to learn about Current, in contrast to Colt, Nolan became more mature and responsible with his power, and less opted to violence to set a good example as a mentor.
Although he's still a fighter with an adventurous spirit, he cares about Colt more than anything else in the multiverse, and anyone trying to do something to him would face a most painful punishment.
("I've only had Arlo for a day and a half. But if anything happened to him, I would kill everyone in this room and then myself." XD)
Nolan now has a strong sense of justice, Colt became like his moral compass, he is also very tenacious and strong-willed as it's necessary for a Current User without his keyboard, traits which he also passed to his apprentice.