Try to do variables in a different way. No idea if it will work.

tasks/miner/software/nanominer.yml

@@ -1,2 +1,35 @@
 ---
 # Nanominer from nanopool.org
+
+## Install ##
+
+
+## Settings ##
+
+- name: Miner | Software | nanominer | Mine with CPU (Optional)
+  debug:
+    var: nanominer_config.cpu
+  when: nanominer_config.cpu is defined
+
+- name: Miner | Software | nanominer | Mine with GPU (Optional)
+  debug:
+    var: nanominer_config.gpu
+  when: nanominer_config.gpu is defined
+
+#- name: Miner | Software | nanominer | Mine with GPU (Optional)
+#  blockinfile:
+#    path: "{{ item }}/.bashrc"
+#    block: |
+#      watchdog = true
+#    marker: '# {mark} MANAGED BY ANSIBLE | Aliases'
+#    state: present
+#    create: yes
+#    backup: yes
+#  loop: "{{ nanominer_config.gpu }}"
+#  when: nanominer_config.gpu is defined
+
+- name: Miner | Software | nanominer | Choose GPUS (Optional)
+  debug:
+    var: "{{ item }}"
+  loop: "{{ nanominer_config.gpus }}"
+  when: nanominer_config.gpus is defined