According to the law..
the tax is exempted in case of nepali citizen returning from foreign country in following case...
One piece each of professional goods used by the

professional passenger( for example for medical doctor

stethoscope and instruments for testing blood pressure, for

players goods like football, volleyball, badminton set,

musician

harmonium, tabla etc);

for

ordinary

musical

instruments

like

guitar,


here are other information..
https://docs.google.com/viewer?a=v&q=cache:eI4BAN8dedUJ:www.customs.gov.np/download.php%3F%26f%3DBaggage%2520Rules%25202066%2520Final.pdf%26dir%3Dcontents+&hl=en&gl=us&pid=bl&srcid=ADGEESjRroikNt-zmqoSP6CFsLL8EL7UO9o2nI_bMcYuQar_sfKaJ6GU3atJjR5Uu1zIkZfB7UvIujzB7sZV54MJH7f-iKYrPv4UJ75thpVZqiYbDMeRKFOOpakcNQO6nbkZ6w1gQJqS&sig=AHIEtbSDGDo1ZgvnVD7jN4NyVYeztlu4vQ