diff --git a/src/natcap/invest/crop_production_regression.py b/src/natcap/invest/crop_production_regression.py
index 003ac96cc..3c18c221f 100644
--- a/src/natcap/invest/crop_production_regression.py
+++ b/src/natcap/invest/crop_production_regression.py
@@ -251,7 +251,7 @@
                         "about": f"{x} {name} production from the crop",
                         "type": "number",
                         "units": units
-                    } for nutrient, name, units in NUTRIENTS
+                    } for (nutrient, name, units) in NUTRIENTS
                     for x in ["modeled", "observed"]
                 }
             }