см. https://www.lingvolive.com/ru-ru/translate/en-ru/night%20out

по-русски, конечно, напрашивается сказать "сегодня вечером мы идем в..." (ресторан, кино, театр, клуб и т.п.)

или " [сегодня у нас] поход в ресторан/театр/..."

Nick, what you’re describing sounds like “We’re going to have a night out.” The only context I can imagine saying “This is a night out” is as a caption for a photo of some people in a restaurant, club or event. Or if a man takes his wife out for an evening without the kids and all she does is talk about them. He can remind her, “Hey, this is a night out.”

Perhaps young Timothy will humor us with an actual context so that we know what to make of this.