I've never taken out out, but judging by the shape of the moulding I'd say it is pushed in from the outside. That shape of that curved barb look likes the end to which the hose is attached is pushed through the hole, the barb flexes down as it's pushed in, then that step at the end of the barb snaps into place to hold it into position. To pull it out from the hole, I expect you have to push down on the tip of the barb to release it. Let's hope the plastic hasn't gone brittle and doesn't snap off. When I look on partsouq it shows the nozzle assembly as having a short length of tubing already attached to it. If you have to use the existing tubing, I suggest you pull the old nozzle out, pull the tubing out through the hole and attach it to the new nozzle before feeding it back through the hole.