When encountering a vehicle in an oncoming lane during nighttime, it is advisable to:

Dimming your headlights when encountering a vehicle in an oncoming lane during nighttime is important for safety and visibility. High beams can be blinding to other drivers, making it difficult for them to see the road and react appropriately. By dimming your headlights, you reduce glare and ensure that both you and the oncoming driver can see each other clearly, which helps prevent accidents.

Using high beams would likely hinder visibility for the oncoming driver and can lead to dangerous situations. Waiting until the vehicle passes could be impractical, especially if you're driving at a speed where waiting would not be safe or if the oncoming vehicle is too close to react in time. Turning off your headlights altogether is not safe, as it would leave you without illumination, making navigation more difficult for you and creating additional hazards.

Thus, dimming your headlights is the best practice to maintain safety for all drivers on the road.