how can i resize nicklist like 3/4 default ?

Resize? Up-Down? Right-Left?

move the mouse to the border of the chan'window/nicklist and drag it bigger/smaller

i think also once you drag/pull it to the size you want you will need to right click on the channel tab and untick "use default size" in the nicklist options .

i meant "up-down"

inside of mirc u cant ... but u can create ur own nicklist using dll and pretty much do whatever u want with it

Get a dll for creating your own nicklist from mIRCScripts.org..