Yes, Nag Tibba trek can be done in a day by experienced trekkers or those who are physically fit and have some prior trekking experience. The trek distance from the base camp at Pantwari village to the summit of Nag Tibba is around 8 kilometers (approximately 5 miles) and can take around 4-6 hours to complete. However, it is recommended to start the trek early in the morning to avoid hiking in the scorching sun and to reach the summit before sunset. It is also important to carry sufficient water, food, and necessary trekking gear such as a raincoat, jacket, and proper trekking shoes. It is worth noting that doing the Nag Tibba trek in a day can be physically challenging, as the trek involves a steep ascent of around 4-5 hours to the summit and then a descent of another 3-4 hours. So, it is advisable to be physically fit and well-prepared before attempting this trek in a day.