refactor(boards): Move nice!nano to ZMK variant by default

Make the standard nice!nano board ID be `nice_nano/nrf52840/zmk` or
`nice_nano//zmk` by shorthand.

app/boards/nicekeyboards/nice_nano/Kconfig.nice_nano

@@ -3,6 +3,6 @@
 
 config BOARD_NICE_NANO
     select SOC_NRF52840_QIAA
-    imply RETAINED_MEM
+    imply RETAINED_MEM if BOARD_NICE_NANO_NRF52840_ZMK
-    imply RETENTION
+    imply RETENTION if BOARD_NICE_NANO_NRF52840_ZMK
-    imply RETENTION_BOOT_MODE
+    imply RETENTION_BOOT_MODE if BOARD_NICE_NANO_NRF52840_ZMK

app/boards/nicekeyboards/nice_nano/board.yml

@@ -1,11 +1,5 @@
 board:
-  name: nice_nano
+  extend: nice_nano
-  vendor: nicekeyboards
+  variants:
-  socs:
+    - name: zmk
-    - name: nrf52840
+      qualifier: nrf52840
-  revision:
-    format: major.minor.patch
-    default: 2.0.0
-    revisions:
-      - name: 1.0.0
-      - name: 2.0.0

app/boards/nicekeyboards/nice_nano/nice_nano.zmk.yml

@@ -1,5 +1,5 @@
 file_format: "1"
-id: nice_nano
+id: nice_nano//zmk
 name: nice!nano
 type: board
 arch: arm

app/boards/nicekeyboards/nice_nano/nice_nano_nrf52840_zmk.dts

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2026 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/dts-v1/;
+
+#include <../boards/nicekeyboards/nice_nano/nice_nano.dts>
+#include <common/nordic/nrf52840_uf2_boot_mode.dtsi>
+

app/core-coverage.yml

@@ -1,5 +1,5 @@
 board:
-  - nice_nano
+  - nice_nano//zmk
   - nrfmicro/nrf52840/zmk
   - proton_c//zmk
 shield:
@@ -18,43 +18,43 @@ include:
   - board: planck//zmk
   - board: proton_c//zmk
     shield: clueboard_california
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: kyria_left
     cmake-args: "-DCONFIG_ZMK_DISPLAY=y"
     nickname: "display"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: kyria_left
     cmake-args: "-DCONFIG_ZMK_POINTING=y"
     nickname: "mouse"
   - board: sparkfun_pro_micro_rp2040//zmk
     shield: reviung41
     cmake-args: "-DSNIPPET='zmk-usb-logging'"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: kyria_right
     cmake-args: "-DCONFIG_ZMK_DISPLAY=y"
     nickname: "display"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: romac_plus
     cmake-args: "-DCONFIG_ZMK_RGB_UNDERGLOW=y"
     nickname: "underglow"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: lily58_left nice_view_adapter nice_view
     nickname: "niceview"
   - board: bdn9//zmk
     snippet: studio-rpc-usb-uart
     cmake-args: "-DCONFIG_ZMK_STUDIO=y"
     nickname: "stm32-studio"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: reviung41
     snippet: studio-rpc-usb-uart
     cmake-args: "-DCONFIG_ZMK_STUDIO=y"
     nickname: "nrf52-studio"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: corne_left
     snippet: studio-rpc-usb-uart
     cmake-args: "-DCONFIG_ZMK_STUDIO=y"
     nickname: "split-left-studio"
-  - board: nice_nano
+  - board: nice_nano//zmk
     shield: corne_right
     snippet: studio-rpc-usb-uart
     cmake-args: "-DCONFIG_ZMK_STUDIO=y"

app/module/boards/nicekeyboards/nice_nano/Kconfig.nice_nano

@@ -0,0 +1,5 @@
+# Copyright (c) 2026 The ZMK Contributors
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_NICE_NANO
+    select SOC_NRF52840_QIAA

app/module/boards/nicekeyboards/nice_nano/board.cmake

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: MIT
+
+board_runner_args(nrfjprog "--nrf-family=NRF52" "--softreset")
+include(${ZEPHYR_BASE}/boards/common/uf2.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/nrfjprog.board.cmake)

app/module/boards/nicekeyboards/nice_nano/board.yml

@@ -0,0 +1,11 @@
+board:
+  name: nice_nano
+  vendor: nicekeyboards
+  socs:
+    - name: nrf52840
+  revision:
+    format: major.minor.patch
+    default: 2.0.0
+    revisions:
+      - name: 1.0.0
+      - name: 2.0.0

app/module/boards/nicekeyboards/nice_nano/nice_nano.dts

@@ -7,7 +7,6 @@
 /dts-v1/;
 
 #include <nordic/nrf52840_qiaa.dtsi>
-#include <common/nordic/nrf52840_uf2_boot_mode.dtsi>
 #include "nice_nano-pinctrl.dtsi"
 #include "arduino_pro_micro_pins.dtsi"
 

app/module/boards/nicekeyboards/nice_nano/nice_nano_1_0_0_defconfig

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: MIT
+
+# Enable MPU
+CONFIG_ARM_MPU=y
+
+# enable GPIO
+CONFIG_GPIO=y
+
+# Use pinctrl
+CONFIG_PINCTRL=y
+
+CONFIG_USE_DT_CODE_PARTITION=y
+CONFIG_BUILD_OUTPUT_UF2=y

app/module/boards/nicekeyboards/nice_nano/nice_nano_2_0_0_defconfig

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: MIT
+
+# Enable MPU
+CONFIG_ARM_MPU=y
+
+# Use pinctrl
+CONFIG_PINCTRL=y
+
+# enable GPIO
+CONFIG_GPIO=y
+
+CONFIG_USE_DT_CODE_PARTITION=y
+CONFIG_BUILD_OUTPUT_UF2=y

app/module/boards/nicekeyboards/nice_nano/pre_dt_board.cmake

@@ -0,0 +1,9 @@
+#
+# Copyright (c) 2026 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+#
+
+# Suppresses duplicate unit-address warning at build time for power, clock, acl and flash-controller
+# https://docs.zephyrproject.org/latest/build/dts/intro-input-output.html
+
+list(APPEND EXTRA_DTC_FLAGS "-Wno-unique_unit_address_if_enabled")