diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0bdf88..3648ee3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Document that `expression` accepts `string`, `object`, or `array`, matching the schema ([#8](https://github.com/stac-extensions/render/issues/8))
+- Clarify that `nodata` overrides any nodata value already defined on the referenced assets for this specific
+  render, rather than duplicating it ([#15](https://github.com/stac-extensions/render/issues/15))
 - Update broken titiler `colormap`/`color_formula` doc links and replace the dead `api.cogeo.xyz` demo host.
   Rework the NDVI example around the still-live Sentinel-2 item, since the Landsat-8 example's source imagery
   was removed from the public `landsat-pds` bucket ([#13](https://github.com/stac-extensions/render/issues/13))
diff --git a/README.md b/README.md
index 6c5f7e5..aac6190 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,7 @@ The fields in the table below can be used in these parts of STAC documents:
 | assets        | \[string] | **REQUIRED**. Array of asset keys [referencing the assets](#assets-reference) that are used to make the rendering                                                        |
 | title         | string    | Optional title of the rendering                                                                                                                                          |
 | rescale       | \[float]  | 2 dimensions array of delimited Min,Max range per band. If not provided, the data will not be rescaled.                                                                  |
-| nodata        | float, string     | Nodata value to use for the referenced assets.                                                                                                                           |
+| nodata        | float, string     | Nodata value to use for this render, overriding any nodata value already defined on the referenced assets (e.g. via the [raster](https://github.com/stac-extensions/raster) extension). If not set, implementations SHOULD fall back to the asset's own nodata value. |
 | colormap_name | string    | Color map identifier that must be applied for a raster band                                                                                                              |
 | colormap      | object    | [Color map JSON definition](https://developmentseed.org/titiler/user_guide/rendering/#custom-colormaps) that must be applied for a raster band                             |
 | color_formula | string    | [Color formula](https://developmentseed.org/titiler/user_guide/rendering/#color-formula) that must be applied for a raster band                                            |