The State Assembly said the two leaders led the executive arm of government to fraudulently divert N10 billon of workers' salaries for September and October 2011; N120 million of Adamawa state workers' emolument for May, 2014; N1.7 billion for Special Assistants; and N8 billion for fictitious contract.
The impeachment notice, signed by 19 of the 25 state lawmakers, listed 20 impeachable offences against Messrs. Nyako and Ngilari.
The House had earlier given the government a week notice to reverse the deductions made from the workers pay, but sources said the governor not only ignored the Assembly, but went ahead to authorize further deductions from last month's pay.
Reading the impeachment notice on Wednesday, the Speaker, Umar Fintiri, said the notice of impeachment is an exercise of the powers vested on the Assembly by section 188 (1)-(9) of the Nigerian 1999 constitution as amended.
On his part, Mr. Nyako's deputy, Mr. Ngilari, is accused of extra-budgetary expenditure of over N390 million as overhead cost from January 2013 to December 2013 among other allegations.
The lawmakers say the expenditure contravenes section121 (4) (a) and (b) of the constitution.
Nineteen of the 25 members of the Assembly also signed the deputy governor's impeachment notice.
This the second time that Mr. Nyako would be served notice of impeachment in his over seven years tenure as governor of the state.
We are vindicated
Meanwhile, a group, Save Adamawa Movement, said the impeachment notice had vindicated it.
The group in a statement on Wednesday said the impeachment notice on Mr. Nyako is a welcome development and was long overdue.
"All the facts adduced by the members are issues we in Save Adamawa Movement have raised as a group for nearly two years now," it said.
The group said it even resorted to court action to let the world know of Mr. Nyako's misgovernance that has "become legendary" and brought down the whole state.
"We had called for his resignation and or impeachment times and over before now.
"We support every effort to set things right by the members, no one should point fingers to the PDP, Presidency or some big men in Abuja. None of these people are involved even remotely in the messy affairs of Governor Nyako.
"We are aware of desperate moves to hang the exercise on primordial sentiments, but we do not see how corruption, nepotism, total lack of administrative ability and a capital failure is any tribe or religious insignia," it said.
Protests in Yola
Shortly after news of the impeachment process circulated around the state, supporters of the governor staged a protest condemning the action of the Assembly.
A resident, Muazu Isiyaku, told PREMIUM TIMES that it took the early intervention of the police to contain the protesters who were threatening to perpetrate violence.
Efforts to get the reaction of Mr. Nyako proved futile as his spokesperson, Ahmad Sajoh, did not answer or return calls.