Tension-Type Headache: This is the most likely diagnosis given the description of bilateral frontal throbbing aching headache with intermittent nausea, especially in the context of a history of chronic headaches. Tension-type headaches are common and often present with such characteristics, although they typically lack the severe intensity and photophobia associated with migraines.

Migraine: Although the patient reports no photosensitivity, migraines can sometimes present without all typical symptoms (aura, photophobia, phonophobia). The presence of nausea and the throbbing nature of the headache could still suggest a migraine, especially if the patient has a history of migraines.
Chronic Daily Headache: Given the patient's history of chronic headaches, this could be an exacerbation of chronic daily headache, which can have various underlying causes, including transformed migraine, chronic tension-type headache, or new daily persistent headache.

Subarachnoid Hemorrhage: Although less likely given the gradual onset and absence of "thunderclap" headache description, it's crucial to consider this diagnosis due to its high morbidity and mortality. Any new or different headache, especially with sudden onset, should prompt consideration of subarachnoid hemorrhage.
Meningitis: The presence of headache and nausea could suggest meningitis, especially if accompanied by fever, stiff neck, or altered mental status. This diagnosis is critical to identify promptly due to its potential for severe consequences if not treated early.
Temporal Arteritis: This condition, more common in older adults, can present with headache, although it typically involves the temporal region and is accompanied by other symptoms such as jaw claudication and visual disturbances.

Idiopathic Intracranial Hypertension (IIH): This condition can cause headaches that are often worse in the morning and can be associated with nausea and visual disturbances. It's less common but should be considered, especially in obese females of childbearing age.
Headache due to Brain Tumor: Although rare, headaches can be a presenting symptom of brain tumors. These headaches are often worse in the morning and can be associated with nausea, vomiting, and neurological deficits.
Cervicogenic Headache: Originating from the cervical spine, these headaches can present with various characteristics, including being unilateral or bilateral, and can be accompanied by neck pain and limited range of motion.