If you go to "Language and Text" in the System Preferences and enable the "U.S. Extended", you can write all of the tones symbols. Option + a gives you the first tone ( zhōng ) Option + e gives you the second tone ( rén ) Option + v gives you the third tone ( nǐ hǎo ) Option + ~ [button below the escape button] gives you the fourth tone ( zài ) If you need further instructions, feel free to ask. :)

no way to type it as nǐ-hǎo at the moment only import

Maybe what you need is a typing software called Sougou Chinese Input.

When you type Chinese, there is no need to type tones in any operating systems. Just type "nihao", with the MacOS Chinese input method, and then you will see a list of words, all have the pinyin of "nihao" but may have different tones. You just need to choose the one you want.

ni hao,ni是第二个音，hao字是第三音。