If the verb you're looking for is shine then use it as so; "The sun shone through the window." In English you can often describe light as acting like a liquid as if it were water. If you do that you can get more creative with things like this. "The sunlight flowed through the window filling the room with warmth." or "The sunshine leaked through the cracks in the blinds making patterns of light all over my floor."

You can also simply say that the sun is coming in, but that doesn't say whether it is nice or not. It might mean you need to close the curtains because it's too bright. In regular speech I would say 'coming', but I like Toby's sentences - much more descriptive.