Part 135 pilot reported during final approach they were cleared to land and had a near miss with another aircraft that was cleared to land on the same runway. The controller immediately told the other aircraft to turn right and go around.

Narrative

I was cleared for the ILS 20 into ALW on an IFR flight plan. Upon checking in with tower; I was told to report COSUV inbound. I did and was cleared to land runway 20. At 600' AGL and inside of 1 mile; with the runway not in sight; tower cleared Aircraft Y to land short approach runway 20. I let tower know I was at 1800' MSL with the runway not in sight on the approach and another controller broke in and asked my position. I said I was short final for 20. He immediately told Aircraft Y to turn right immediately and go around runway 20. I broke out on the approach at approximately 300' AGL and saw Aircraft Y on a right base making a hard right turn to parallel runway 20. I estimate the distance to be inside of 1500' laterally and 100' vertically. After landing I asked the tower what just happened and was only given the response of 'Controller in training'. I checked the ASOS after parking and the weather was 200' OVC (Overcast). No idea how Aircraft Y was even in the pattern while the airspace was IMC; let alone how it was cleared to land in front of inbound IFR traffic. The tower nearly caused a mid-air collision.