An observation about her character I wanted to share. Nora only teases those close to her or on the other end of the spectrum, people she is deliberately trying to throw off.
Nora tends to tease people she believes are close enough to her to not take offense to it.
(Here she pokes fun at Qilby, who is entirely unbothered by it)
(He actually teases her back later on)
Unfortunately, she misjudges her closeness to Yugo and irritates him multiple times
She actually drops teasing him after he directly tells her it's getting on his nerves.
So, with the people she values, it's not actually meant to upset them, and she does it in a playful manner. It seems like she does it as a way of trying to lighten the mood (she often does it during stressful situations such the volcano erupting or the necro attack in Yugo's home town) or to harmlessly poke fun at them.
With her enemies, however, she very much intends to anger them.
It seems she does it in combat to give herself the advantage. When an opponent is angry, they're not likely to be in a clear enough state of mind to plan things out, and this is exactly what Nora capitalizes on.