Valorie would not be prone to looking up to someone who got bullied a lot. Her asperations are to be respected, after all. If anything, Nika's tendency to not care would actually annoy her. Whoops. Owo
Also, about Pokemon Fallout. Where is your character so we can make this happen?
In that case, Nika left on her journey a minimum of two years before Valorie even got her charmander. Nika returned home only about twice after she began her journey - so perhaps Valorie remembers her more as the returning trainer rather than the weird bullied kid?
Nika changed a lot after she started her journey, she became a lot more outwardly confident in the sense that negative attention seemed to wash right off her - not that she went around braggarting or boasting. Perhaps Val saw her as quite a cool figure to aspire to, and can be suprised when they meet/if they battle at how crazy strong Val is compared to Nika?
I'm just spitballing here though, feel free to jump in with whatever.
Valorie wouldn't intentionally bully anyone. Her large ego is a result of a deep seated desire to earn the respect of others, something that bullying .... honestly doesn't /get/. Hence, no motivation.
Valorie got Charmander less than a year ago. She basically spent about a week or two training hardcore and then tried to challenge Iccirus' Gym and got roflstomped. She almost immediately wound up joining the academy after that, because to be blunt she freaked right the heck out over losing.
Well, I noticed that Nika is a year older than Valorie, but significantly weaker, so we can have some fun with that when they re-meet. Nika spent so much time travelling around to get the pokemon she wanted, she won't have had as much time to devote to training.
As far as a tie in from when they were back at home, one doesn't appear as obvious to me. Valorie doesn't seem like the type that would bully Nika, an older girl, for being a bit odd when Val has some oddness about her herself. How old was Val when she got her charmander after the bird-on-the-head incident?