2001 Nissan Altima GLE sensor?

I was replacing the thermostat on my 2001 nissan altima. I decided to check all the connections on the cooling system and noticed on top of the water outlet port (right below the alternator) the sensor was very loose. I am not sure what this sensor is called. I am trying to figure out what it is so I can replace it. I did some research and found it could be the coolant temperature sensor but when I look it up it comes up with a few different parts. Can anyone verify that this sensor on the water outlet port coming from the engine is in fact the CTS? The picture attached is the water outlet from the engine. The hole on the top is where the sensor was removed.