Replace NEXUS_BOARD with NEXUS_ID

BUG: 316200811
Change-Id: I71cc6079bbab8dcc70840aaddedef8a488a4ead1
diff --git a/nexus-non-interactive-test.sh b/nexus-non-interactive-test.sh
index 93e1760..d0a23e9 100755
--- a/nexus-non-interactive-test.sh
+++ b/nexus-non-interactive-test.sh
@@ -112,7 +112,7 @@
         --usb-serial "Nexus-FTDI-${NEXUS_ID}" \
         bootstrap "${BINARY_PATH}"
 elif [[ "${BINARY_PATH}" == *"extflash.tar" ]]; then
-    export NEXUS_BOARD="${NEXUS_ID}"
+    export NEXUS_ID
     export OT_TOOL="${OT_TOOL_PATH}"
     export NEXUS_JSON="${NEXUS_JSON_PATH}"
     "${NEXUS_FLASH_PATH}" "${BINARY_PATH}"