How can I show raster pixels with NoData value in QGIS?
In ArcMap there is a button to choose the color for the NoData value. Is there something like this in QGIS?
You can display raster NoDataValue in LayerProperties / Transparency tab by unchecking the "No data value" checkbox and "adding values manually" to the "transparent pixel list" table (green plus sign). After adding a value one need to change the "Percent Transparent" column to zero. After Applying this you can see the padded values as black.
If you are having trouble displaying no data values, try using a Render Type of either Singleband Pseudocolor or Paletted/Unique Values. The Render Type that you choose needs to support adding cell values in order to be able to add the no data value. These two Render Types allow for adding cell values.
If using an Interpolation Type of Discrete, the no data value may need to be changed in the Value / Color / Label section to be slightly different from the actual no data value. For example, if your no data value is -999.99, try changing it in the Value / Color / Label section to -999.98. Seems like a bug, but perhaps I am not understanding.
The above was done in QGIS version 3.16.4 (Hannover).