http://www.customs.gov.np/contents/Procedure/Passenger-Clearance/6/
For television sets, you can just use the following guidelines:
(For those who are returning back after spending more than 6 months abroad)
0тА│ тАУ 22тА│ Rs 250 /inch
23тА│ тАУ 29тА│ Rs 350 /inch
30тА│ тАУ 32тА│ Rs 640 /inch
33тА│ тАУ 39тА│ Rs 800 /inch
40тА│ тАУ 49тА│ Rs 850 /inch
50тА│ тАУ over Rs 1600 /inch
(For those who are returning back after spending less than 6 months abroad)
0тА│ тАУ 22тА│ Rs 300 /inch
23тА│ тАУ 29тА│ Rs 425 /inch
30тА│ тАУ 32тА│ Rs 720 /inch
33тА│ тАУ 39тА│ Rs 900 /inch
40тА│ тАУ 49тА│ Rs 950 /inch
50тА│ тАУ over Rs 1700 /inch
Bottom line is, it is stupid idea to take television sets with you as it is going to be very expensive.