You can also do NicknameLastname.com, which is what I did to create LaerCarroll.com. For decades all my friends called me Lair, two syllables of verbal effort being too important to waste on me. Luckily I found that Laer is one if the spellings of the Gaelic dialects for Ler, God of the Sea. And meaning "wise" in another dialect. Being Irish I seized on that spelling for my nickname.

IndianaJones is another example.

You may want to use a middle name or initial instead of your first name, or in addition to it. Examples include PhillipJoseFarmer.com and PhilipKDick.com.

I'd suggest you find a domain name which you can also use as a pen name. This avoids confusing your readers, business partners, and libraries.