It's like a matryoshka, and talking about Russia (or Ukraine, for the matter) you shouldn't forget about it. The Russians are not only Russians, ok?
By the way, your word 'nationality' is also often confusing for us, being a 'false translator's friend'. The Russian word "национальность" of the same Latin origin means 'ethnicity', not state citizenship. And ethnicity means a lot in such a multi-ethnical country (or empire — I don't care) Russia is.
We have about 100 (one hundred) ethnicities counting more than 100 thousand people each, and in general our last census recorded about 350 ethnicities. Wiki has a good table on the matter. And all these people, being Buryats, Ossetians, Yakuts, Mansi's and many many other names, are Russians by nationality; definitely including close to 80% of Russian Russians.
What is important in all this Ukrainian madhouse spreading its infection worldwide, by the way, is that Ukraine is also a multi-ethnical country, though evidently to a lesser extent than Russia. And with the tiny little history of just 23 years after the disintegration of the USSR; Ukraine never existed as a self-standing independent state before, except for about one year during the bloodiest Civil War which exploded in Russia after Antanta decided to support anti-Bolshevik forces soon after the October Revolution.
Here, I'd like to remind you of a Gallup pool conducted in 2008. It clearly shows that 83% of Ukrainian population preferred to respond in Russian, and only 17% responded in the Ukrainian language. Nevertheless, the Russian language in Ukraine is not official; the language problem, worsened by active, and even aggressive ukrainization, was definitely one which lead the country to the present state of civil war.
So, as for Ukraine, people who are Ukrainians by nationality, can be ethnically Ukrainian speaking Ukrainians, Russian speaking Ukrainians, Russians (by their Ukrainian own census about 8 millions, yet the figure seems to be artificially decreased), and a number of ethnical minorities, including Crimean Tartarts (they have their own Turkic language), Hungarians and many others in Trans-Carpatian region.
So, talking about Russian and Ukrainian problems, you are to clearly understand what you are talking about now: nationality and citizenship, or ethnicity. And the latter issue is not less important on the territory of the former USSR; in Soviet passports there was a special line for ethnicity. Yet, especially in cities with well established industry, there were many interethnical marriages, when the husband could be Russian and wife Ukrainian, or Armenian and Azerbaijani, or Buryat and Komi, or Tartar and Jewish, etc. And it was the parents' joint decision, what ethnicity was to be written into the special field of birth certificates of their children, and later in their passports.
As for me personally, I am definitely Russian, I belong to Russian culture, Russian is my native language. In the time of Russian Empire my ethnicity was called 'Velikoross' (Great Russian), and the biggest were 'Malorossians' ('people of Small Russia', Ukrainians) and 'Belorussians' (people of White Russia'). Yet my blood includes drops of some other ethnicities, as it is common for many of my compatriots. I know that one of my great-grandmothers was a Crimean Tartar. I also can have a tiny little drop of Polish blood: one of my grandfathers came from a village in Ryazan' region of Russia, where captured Polish POWs were forced to settle back in the 17th century, and his family name 'Polyakov' (literally, "of Polish origin") can be a sign of it. But many of my friends and colleagues, and my classmates, and university-mates are and were Russian Armenians, Russian Tartars, Russian Jews, etc.
Just to finish. When the USSR was strong, the ethnical matter meant less; the social lifts were open to all ethnicities, and many colleges and institutes were obliged to teach a certain percentage of students coming fron ethnical minorities. With the disintegration of the USSR, ethnical issue arose in its full strength in some regions, and lead to many mass riots and bloody conflicts, mainly in the Asian and Caucasian parts of former Soviet Union. Who is a current 'nationalist' in Russia (not necessarily Russian ethnically)? The one standing for his (or her) ethnicity, not nationality.
I consider it as a great disaster and civilizational regress, as no ethnicity in my opinion is better than others. My younger son is a sportsman, a figure skater, and a skating rink is a nice place to show who is stronger, quicker and can jump higher. AK-47 is the worst way to prove one's advantage over others.
That's all for now; yet I feel the matter is so important that I will go back to it from time to time to dig some aspects deeper, and sometimes I will definitely touch it in my publications.