Live streaming video with a Nikon DLSR & MacBook?

I have a wedding I need to stream on Saturday and I was wondering how I can do that with my nikon d5300. How to connect it to the mac, then live stream it and send the link to people…

No model number? Probably not not going to happen without more parts. Assuming you mean video streaming, you should probably read the camera manual - specifically the pages that refer to the camera automatically shutting down after prolonged (usually about 20 minutes) video capture because of overheating. The other parts about auto shutdown after not being used (not recording) is probably a good idea, too. And the parts about automatic shut down after 29 minutes, 59 seconds (assuming it did not shut down from overheating, first) is probably something else you need to know about.

A dSLR is not a studio, security or video camera. And a dSLR is not a camcorder - unless yours is like mine and was designed for video capture (Canon EOS C500, Sony NEX-EA50UH). More than likely, it is designed to capture still images. This does not mean it can't capture good video - it can, but video (and audio) is a "convenience feature" and most dSLRs under about $1,500 need lots of workaround skill (and practice) to be used in a manner that is not its primary design. Plus what you want to do is not capture (then edit).

Take a look at the Blackmagic Designs converters - specifically the Intensity Shuttle boxes. AV-out to HDMI out from the camera into the video converter box and the converter box connects to the computer. You did not tell us which MacBook. Personal computers are not designed to be video streaming work stations. And we don't know which streaming service you think you will use.

It is best to set everything up and be sure it all works before the event. You won't have much time to do that.

You can live stream to Livestream if you use one of their boxes

http://new.livestream.com/broadcaster

You'll also need some sort of network connectivity - and we don't know what is available where you will be capturing the video.

I agree with Mmm J - overheating could shut down the dSLR and the broadcast would end abruptly.

With little prior planning or practice, this appears to have failure written all over it.