I find that Snow has the opposite problem as Elsa: she is frequently just typed as a sensor (because you know, she's all traditional and not adventurous and likes to cook and all that boring sensor stuff, right?). There's a lot of bias and stereotyping with MBTI fans, and I used to be guilty of it too (OK, sometimes I still
am). though to be fair, I think Snow IS a little underdeveloped in ways, so she could really be interpreted either way. However, I'll explain why I think she uses Ni over Si.
Extraverted Feeling (Fe):
No doubt about it, Snow White is warm, caring, and a social butterfly. She enjoys engaging with others, even the forest animals, and having parties. When she first arrives at the cottage, she immediately sympathizes with the "orphans" living there. She immediately warms up to the Dwarfs and takes over their little cottage like it's her own business as a mother figure. She's outspoken and honest. After being treated like a slave by her only family member, she still wishes to find love and hear "the nice things he'll say". In addition to that, her prayer to make Grumpy like her indicates she needs affirmation from others. She is respectful of others, always mindful of her manners, and likes to tease her friends a little bit to make them laugh, never taking offense herself when Grumpy is rude to her. Her worst flaw in the iconic apple scene is that she is polite to a fault: she can't just tell the "poor old lady" no and be rude! She knows not to let strangers in but her heart reaches out to someone she sees as suffering and has to help them.
Introverted Intuition (Ni):
Snow White is very dreamy, deeply romantic, and just knows that her prince will find her while she's in hiding (and she's right!). She likes to daydream about her hopes and dreams while she works hard. She believes in fate and magic and after some initial hesitation, she takes the old peddler up on her offer of the magic wishing apple, with its promise to make her dreams come true. She's optimistic to a fault and trusts her instincts, like letting the old lady into the house, despite the dwarfs' warning and the animals' protests.
Extroverted Sensing (Se):
Snow White can be a little impulsive. Like I said, her first action is to let the old lady into the house without really thinking, and then after some nervousness decides to take a chance and eat the apple to get what she wants. She likes to make herself look good and is embarrassed to have her crush see her in dirty rags. She likes to bake and thinks giving Grumpy a delicious pie might cheer him up. In fact, she convinces them to let them stay by trying to appeal to their sweet tooth! She's observant and notices how small and dirty the place is and draws conclusions based on that. She's not very adventurous but isn't afraid of being forced out of her comfort zone.
Introverted Thinking (Ti):
Snow White tends to make more emotionally-based decisions, but she is analytical, deducing who must live at the cottage and easily figures out which Dwarf Grumpy is, sarcastically (if sweetly) pointing it out.