Sanity-check the chamber thermistor pin

Marlin/src/inc/Conditionals_post.h

 #if ENABLED(JOYSTICK)
   #if PIN_EXISTS(JOY_X)
     #define HAS_JOY_ADC_X 1
-#endif
+  #endif
   #if PIN_EXISTS(JOY_Y)
     #define HAS_JOY_ADC_Y 1
-#endif
+  #endif
   #if PIN_EXISTS(JOY_Z)
     #define HAS_JOY_ADC_Z 1
-#endif
+  #endif
   #if PIN_EXISTS(JOY_EN)
     #define HAS_JOY_ADC_EN 1
-#endif
+  #endif
 #endif
 
 // Heaters

Marlin/src/inc/SanityCheck.h

   #error "TEMP_SENSOR_7 shouldn't be set with only 1 HOTEND."
 #endif
 
+#if TEMP_SENSOR_CHAMBER && !PIN_EXISTS(TEMP_CHAMBER)
+  #error "TEMP_SENSOR_CHAMBER requires TEMP_CHAMBER_PIN. Please add it to your configuration."
+#endif
+
 #if TEMP_SENSOR_PROBE
   #if !PIN_EXISTS(TEMP_PROBE)
-    #error "TEMP_SENSOR_PROBE requires TEMP_PROBE_PIN."
+    #error "TEMP_SENSOR_PROBE requires TEMP_PROBE_PIN. Please add it to your configuration."
   #elif !HAS_TEMP_ADC_PROBE
     #error "TEMP_PROBE_PIN must be an ADC pin."
   #elif !ENABLED(FIX_MOUNTED_PROBE)

Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h

   #define TEMP_BED_PIN                  P0_23_A0  // A0 (T0) - (67) - TEMP_BED_PIN
 #endif
 
-#if HOTENDS == 1 && TEMP_SENSOR_PROBE
-  #define TEMP_PROBE_PIN              TEMP_1_PIN
+#if HOTENDS == 1
+  #if TEMP_SENSOR_PROBE
+    #define TEMP_PROBE_PIN            TEMP_1_PIN
+  #elif TEMP_SENSOR_CHAMBER
+    #define TEMP_CHAMBER_PIN          TEMP_1_PIN
+  #endif
 #endif
 
 //