Probably not the "easy" way, because it's not graphical. But it is kinda pretty easy.
Open terminal (press cmd+space and type "terminal")
First type "diskutil list" and press enter (always without the inverted commas)
then insert your usb stick and run "diskutil list" again to see the disk node (e.g. /dev/disk2)
Now run "diskutil unmountDisk /dev/diskN" (where N is the number of the usb stick)
and then run "sudo dd if=/path-to.iso of=/dev/rdiskN bs=1m"
(after typing "sudo dd if=" you simply copy paste the path that's to be found when you right click on the file, then click "get info" and copy the path under "Where")
When finished "diskutil eject /dev/diskN"
