* Oh my!
* Goodness!
* Oh dear!
* My goodness!
* Wow!
It's used to express surprise, shock, concern, disappointment, or even amusement.
Here are some examples:
* "Nako, ang init!" - Oh my, it's so hot!
* "Nako, nakalimutan ko ang susi!" - Oh dear, I forgot my key!
* "Nako, ang galing mo kumanta!" - Wow, you sing so well!
The tone of voice and context will determine the exact meaning of "nako".