How do you want the username to appear?
Here's what I do:
(defun name ( / namlist)
(setq namlist '(("ALLEN" "ASJ")
("ANJIE" "AJB")
("AUDRA" "AMD")
("BRENT" "BAP")
("BRUCE" "CBN")
("CELESTE" "CKS")
("DESIREE" "DEM")
("ERIC" "ECW")
("JON" "JDL")
("KEN" "KRV")
("LUC" "JDL")
("MARKH" "MJH")
("MARKM" "MAM")
("RON" "RLB")
)
nam (strcase (getvar "loginname"))
)
(if (assoc nam namlist)
(cadr (assoc nam namlist))
(substr nam 1 3)
)
)
Then set a USER variable to the intials:
(setvar "USERS1" (name))