場合(ばあい)はIn the event of, In the case of

なら and ばあいは (often in kanji as 場合は) both correspond to 'if', but with different nuances. なら expresses 'if it's the case that (A)', often implying the speaker believes it will happen, e.g. 来るなら 'if it's the case that (they) come'. In contrast, ばあいは means 'in the event that (A)', presenting a possible situation without assumption, e.g. 来る場合は 'in the event that (they) come'.

ばあいは and としたら・とすれば・とすると both express the idea of 'in the case of' or 'in the event that'. In general, ばあいは (often written in kanji as 場合は) is more concrete and used for specific situations that might arise. For example, 行く場合 'in the event that you go'. In contrast, としたら・とすれば・とすると is typically used to discuss more hypothetical scenarios.

ばあいは (often written in kanji as 場合は) and に取って (often written in kana as にとって) can overlap in some cases, but not all. For example, 私の場合は and 私にとって can both mean 'as far as I'm concerned' or 'in my case'. However, since にとって simply means 'concerning', it can't replace ばあいは for the meaning of 'in the event that', e.g. 行く場合は気をつけたほうがいい ('In the event that you go, you should be careful.').

ばあいは and 万が一 are related in that both refer to potential situations. ばあいは (often written in kanji as 場合は) means 'in the case of' or 'in the event that'. For example, 行く場合は 'in the event that you go'. On the other hand, 万が一 is typically used at the start of a sentence to highlight a rare or unlikely case. Because they serve different roles, the two can even be used together, e.g. 万が一の場合は 'in the unlikely event that (A)'.

と and ばあいは can both express conditions, but differ significantly in usage. と describes something that happens habitually or as a natural result, e.g. お酒を飲むとすぐ酔っ払ってしまう ('When I drink alcohol, I get drunk quickly.'). ばあいは is used more for situational instructions, like お酒を飲む場合は運転しないほうがいい ('In the event that you drink alcohol, you shouldn't drive.').