に行かなきゃ

have to go to

→ に
phrase Uncommon #19,355
have to go to Informal contraction of に行かなければいけない or に行かなくてはならない. The に usually marks the destination or purpose, and the phrase can also mean “gotta go to.”
JA: 明日は病院に行かなきゃ。
EN: I have to go to the hospital tomorrow.

なんで私がボストンに行かなきゃいけないの

Why do I have to go to Boston?

アメリカに行かなきゃならねえのはおれたちの方だよ

We're the ones who have to go to America.

— 紅の豚 (1992)

今日はお葬式に行かなきゃいけないの

I have to go to a funeral today.

に行かなきゃ

I have to go to cram school.

掘りに行かなきゃ

I have to go digging.

— ザ・マン・フロム・アース (2007)

ニワトリに餌をやりに行かなきゃ

I have to go feed the chickens.

オーストラリアに行かなきゃいけないかもしれないんだ

I might have to go to Australia.

君は直ぐあっちに行かなきゃ

You need to go over there right away.

トムは来週オーストラリアに行かなきゃいけない

Tom has to go to Australia next week.