Diana L. Nichols


Diana L. Nichols is Senior Counsel in the firm’s Litigation and Environmental & Water Law practices.  She began her legal career as an associate at Bickerstaff Heath Delgado Acosta LLP and then served as co-managing partner of Gilman, Nichols, Hebner & Rixen PC before joining Kelly Hart & Hallman.

Ms. Nichols has extensive experience in environmental and water law, including water use in the energy sector, mining, water quality, water rates, groundwater regulation, air quality, and electric rates. Additionally, she has handled various commercial litigation cases in state and federal courts, with a primary focus on creditors’ rights.



  • Counsel in TCEQ contested case hearing regarding a Class III injection well area permit application aquifer exemption and application for a production area authorization for a new in situ uranium mine; received favorable decision from Commission on all issues
  • Counsel for protestant in TCEQ landfill application contested case, focused on groundwater-related issues; application rejected by the agency.
  • Lead trial counsel in a lawsuit for judicial review of an air quality permit issued by the Texas Commission on Environmental Quality (TCEQ) to authorize a new bentonite mineral crushing plant. Obtain temporary injunctive relief to prevent plant construction from proceeding
  • Trial counsel representing a municipality in a dispute with a provider of energy management services regarding the terms and price at which gas and electricity was procured for the municipality’s wastewater treatment plant. Successfully negotiated a favorable settlement through mediation
  • Co-counsel representing an owner and operator of a manufacturing plant in a dispute with a municipal-owned utility regarding the electric rate to be charged pursuant to an economic development agreement. Successfully negotiated a favorable settlement through mediation


  • Creditors’ Rights Litigation: representation of creditors in negotiating workouts and in all aspects of litigation, including the defense of lender liability claims and the enforcement of creditors’ rights in both trial court and bankruptcy court, and obtaining and enforcing judgments
  • Complex Litigation: specific experience includes a broad range of complex litigation cases, such as those involving contract disputes, statutory construction, commercial torts, trademark rights, securities claims, and class actions
  • Real Estate Litigation: representation of special asset management companies, landlords, property owners’ associations, and real estate developers in disputes regarding easements, encroachments, deed restrictions, leases, ownership, and title
  • Lead counsel in federal court lawsuit to enforce half a million dollar promissory note in the face of several lender liability counterclaims and challenge that the note was invalid because the corporate agent who executed it lacked authority
  • Lead trial counsel in lawsuit to construe restrictive covenants. Opponents sought to restrict development to single-family housing only. Developer was instead allowed to develop a commercial complex
  • Lead counsel representing owner of a partial interest in a promissory note and deed of trust lien. Obtained injunctive relief against co-owner and then obtained summary judgment allowing judicial foreclosure of the lien
  • Co-counsel in federal court lawsuit to determine priority of two competing liens against a hotel and resort. Obtained judgment declaring that client’s lien was superior
  • Co-counsel in federal court lawsuit to enforce guaranty of $6.5 million promissory note in the face of numerous lender liability counterclaims. Tried the case and obtained judgment in favor of lender for full amount owed
  • Represented holder of multi-million note secured by real estate in negotiating work-out agreement with borrower
  • Lead counsel in lawsuit to defend the validity of a deed conveying several properties against challenges that the deed was invalid due to fraud, undue influence and lack of mental capacity
  • Austin Bar Association, Financial Institutions Section
  • Travis County Women Lawyers’ Association
  • Texas Tech University School of Law, J.D., summa cum laude, 1992
    • Texas Tech Law Review
      • Board of Editors, 1991-1992
      • Staff Member 1990-1991
    • Order of the Coif
  • Texas State University, magna cum laude, 1988
  • State Bar of Texas, 1992
  • U.S. District Court, Northern District of Texas, 1994
  • U.S. District Court, Western District of Texas, 1995
  • U.S. District Court, Southern District of Texas, 2004
  • U.S. District Court, Eastern District of Texas, 2016